Browse Topic: Metals

Items (33,809)

FITTING END, ACORN, SHORT FLARELESS, DESIGN STANDARD

AS4703B (Current)

9/17/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING END, FLARELESS, BLUNT NOSE, DESIGN STANDARD

AS4458C (Current)

9/17/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Development and Production of Weight-Reduced Steel Hat Brake Discs: A Contribution to Automotive Lightweighting

2026-01-0821

9/14/2026

The automotive industry's transition towards electrification, particularly in the passenger car (PC) and light commercial vehicle (LCV) segments, has intensified the focus on vehicle lightweighting to maximize battery range and efficiency. Conventional brake systems in electric vehicles (EVs) are subject to minimal mechanical wear due to regenerative braking, making corrosion the primary cause of component failure and replacement. This paper details the development and production of an innovative lightweight brake, which addresses these challenges. The "Cast-In" brake disc combines a traditional gray cast iron friction ring with a pre-finished, deep-drawn steel hat through a specialized composite casting process. This design achieves a significant reduction in unsprung mass—1.6 kg per disc in a 390mm x 36mm example—directly contributing to improved vehicle dynamics and energy efficiency. Key manufacturing challenges, including ensuring a robust material bond, preventing casting defects, and sealing the steel hat during casting, have been overcome through advanced process controls, simulation, and a patented sealing system. Furthermore, a novel, enhanced corrosion protection system has been developed and validated to meet the required service life of over 10 years, addressing the specific demands of e-mobility. With production scheduled to begin in April 2026, this technology is a milestone for modern braking solutions in the era of electrification.

von Reth, Thomas

Influence of Ferritic Nitrocarburizing with Smart-ONC® on the Modal and Damping Behavior of Gray Cast Iron Brake Rotors

2026-01-0798

9/14/2026

Ferritic nitrocarburizing (FNC) with in-process post-oxidation has been developed as a production-capable surface engineering solution for gray cast iron (GCI) brake rotors to meet the Euro 7 non-exhaust particulate emission limits. While prior investigations have demonstrated significant PM₁₀ reduction, improved corrosion resistance, and stable braking performance, the influence of FNC on noise, vibration, and harshness (NVH) performance requires systematic evaluation. This study quantified the relative contributions of the alloy composition, rotor geometry, and FNC treatment to the modal frequency and damping behavior. Seven ventilated disc types from multiple foundries were characterized to assess the composition-driven variability. In addition, 120 production discs (ventilated and solid) were measured before and after FNC processing to isolate the treatment effects. Modal properties were obtained using impulse-hammer testing under free–free boundary conditions in accordance with VDA 301, and damping was evaluated using the half-power bandwidth method (Q-factor). The results show that the natural frequency is governed primarily by geometric parameters, scaling with the friction-ring thickness and disc diameter. In contrast, the damping behavior is dominated by the alloy composition and graphite morphology. Variations in silicon, chromium, and carbon equivalent produced a 3–4× difference in the Q-factor across foundries. FNC treatment had a negligible effect on the natural frequency (<1%) but produced a measurable increase in the Q-factor, typically 7–10% for solid discs and 22–32% for ventilated discs. The findings establish a clear hierarchy of influence: composition controls the damping, geometry controls the frequency, and the FNC introduces a secondary shift. Within production-relevant composition windows, FNC + Smart-ONC® does not represent a limiting factor for the NVH performance of Euro 7–compliant brake systems.

Awe, Samuel Ayowole, Holly, Mike, Winter, Karl-Michael

Application of Electrochemical Noise Analysis for Rapid Assessment of Corrosion Resistance in Anodized AlSi Alloys

2026-01-0803

9/14/2026

This study presents a rapid and fully quantitative method for evaluating the corrosion resistance of anodized Aluminum-Silicon (AlSi) alloys through Electrochemical Noise Measurement (ENM). Laboratory specimens and brake components of EN AC-45300 (AlSi5CuMg) are anodized and characterized using both ENM and Neutral Salt Spray (NSS) testing to establish a correlation between the two methodologies. The results reveal a clear and consistent relationship between the logarithm of the noise resistance (Log(Rn)) and the NSS exposure time, demonstrating that ENM captures the key electrochemical features governing corrosion initiation. By providing an objective and data-driven assessment based on measurements acquired within approximately 40 hours, ENM offers a significantly faster and more quantitative approach for predicting NSS performance, thereby reducing validation times of anodized AlSi components.

Abello, Mary Angel, Mezzomo, Lorenzo, Mataloni, Valentina, Bonfanti, Andrea, Bertasi, Federico

Thermomechanical Fatigue Life Prediction of Grey Cast Iron Brake Rotors Using Advanced Material Models and Elastic-Plastic Fracture Mechanics

2026-01-0816

9/14/2026

A unified thermomechanical fatigue (TMF) life-prediction methodology is presented for lamellar graphite (grey) cast iron brake rotors operating under the severe transient thermal loads that arise in brake dynamometer durability testing. The workflow links four ingredients within a single rotor-level framework: transient nonlinear finite-element analysis, temperature-dependent inelastic constitutive modeling, a mechanism-based short-crack TMF damage model, and an elastic-plastic (nonlinear) fracture-mechanics crack-growth simulation. Two constitutive descriptions are exercised for the structural analysis — the standard rate-dependent Chaboche viscoplastic model available in Abaqus, and a user material subroutine (UMAT) that couples Chaboche viscoplasticity with continuum damage in order to reproduce the tension–compression asymmetry of cast iron. The resulting stress, strain, and temperature histories drive a multiaxial thermomechanical fatigue Damage (DTMF) computation that estimates crack initiation and early extension, after which a nonlinear fracture-mechanics procedure simulates crack-front advance toward through-thickness failure. Both constitutive models correctly localize the crack-initiation site on the rotor inner diameter, consistent with the dynamometer observations; for the loading histories examined, the standard Chaboche model yields lives in closer agreement with test. The crack-growth simulation reproduces the rapid post-initiation propagation seen experimentally and resolves branch-wise differences in crack-front evolution through the rotor section.

Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah

Study on the Friction Characteristics of Disc Brakes with Ceramic Surfaces for High Performance Vehicle

2026-01-0827

9/14/2026

In this study, various methods were reviewed to simultaneously satisfy the high-temperature braking performance required for high-performance vehicles and the brake dust criteria by environmental regulations. Among them, the characteristics of two types of Brake disc with ceramic composite surfaces were evaluated to prevent disc wear even under the condition of using metallic friction materials with excellent fade performance. As a result of the evaluation, carbon ceramic disc without metal-to-metal contact during braking showed superior characteristics compared to hard metal cladding disc.

Kim, Yoon Cheol, Yeongwoo, Cho, Kim, Youngmin

FITTING ASSEMBLY, 45° ELBOW, EXTERNAL SWAGE TO FEMALE FLARELESS, HYDRAULIC

AS6468A (Current)

9/11/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING ASSEMBLY, TEE, FEMALE FLARELESS TO EXTERNAL SWAGE ON RUN, EXTERNAL SWAGE ON BRANCH, HYDRAULIC

AS6471A (Current)

9/11/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING, TEE, MALE FLARELESS TO EXTERNAL SWAGE ON RUN, FEMALE FLARELESS ON BRANCH, HYDRAULIC

AS8575A (Current)

9/11/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING ASSEMBLY, TEE, EXTERNAL SWAGE ON RUN, FEMALE FLARELESS ON BRANCH, HYDRAULIC

AS6489A (Current)

9/11/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING ASSEMBLY, 90° ELBOW, EXTERNAL SWAGE TO FEMALE FLARELESS, HYDRAULIC

AS6475A (Current)

9/11/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Conceptual Design of Steel Shell-UHPC Composite Pylon for Large-Span Suspension Bridges

2026-99-1513

9/11/2026

With the rapid development of the transportation industry, heavy-duty traffic has become extremely common, particularly in some coastal port cities where the presence of container terminals leads to generally high vehicle axle loads. In these regions with an advanced transportation industry, large-scale cross-sea bridges are often required to ensure transport efficiency. However, conventional long-span bridge types, such as cable-stayed bridges and suspension bridges, face challenges in meeting the demands of heavy-duty traffic due to limitations imposed by the self-weight of pylons. In response, this paper proposes a prefabricated steel shell–ultra high performance concrete (SS–UHPC) composite pylon composed of basic SS–UHPC units, aiming to enhance both the load-carrying efficiency and seismic performance of the structure. A conceptual design of the SS–UHPC composite pylon was developed based on a super-long-span suspension bridge with a main span of 2180 m, and a comparative analysis was carried out against a conventional steel shell–normal concrete (SS–NC) composite pylon. The results show that, owing to the higher strength-to-self-weight ratio of UHPC, the SS–UHPC composite pylon achieves a 42.4% reduction in self-weight compared to the SS–NC composite pylon. Under the most unfavorable load condition, the axial force and transverse bending moment at the pylon base are reduced by 13.79% and 6.24%, respectively. Under maximum seismic load, the axial force and transverse bending moment at the base decrease by 14.12% and 28.92%, respectively, demonstrating improved load-carrying efficiency and seismic performance of the pylon. Although the life-cycle cost of the SS–UHPC composite pylon is higher than that of the SS–NC composite pylon, its superior mechanical behavior sufficiently offsets the cost difference. In conclusion, the superior mechanical behavior of the SS-UHPC composite pylon makes it better suited for application in long-span bridges subjected to heavy-duty transportation loads.

Chen, Jing Li, Liu, Yong Jian, Peng, Hong Bo, Sun, Li Peng, Yang, Ze Hong

Ultrasonic Frequency-Domain Reverse-Time Migration Imaging Incorporating Element Directivity Correction

2026-99-1419

9/11/2026

The finite width of ultrasonic array elements results in a non-uniform angular radiation pattern of elastic waves in solids, deviating from the ideal point-source assumption commonly adopted in reverse-time migration (RTM). This angular radiation non-uniformity produces a crack tip-dominated imaging amplitude with weak crack flank representation, manifesting as a pronounced depth-dependent amplitude imbalance along vertically oriented defects. As a result, cracks may be misinterpreted as point reflectors, which compromises the reliability of characterization in ultrasonic nondestructive testing (NDT). This study proposes an ultrasonic frequency-domain reverse-time migration (FDRTM) imaging method incorporating element directivity correction. A longitudinal-wave directivity model in solids is formulated in the frequency domain and normalized at each frequency to ensure consistent scaling during multi-frequency stacking. During backward wavefield reconstruction using full matrix capture (FMC) data, the angular-dependent energy distribution associated with the receiving direction is explicitly corrected, rebalancing the angular energy distribution in the reconstructed wavefield. Defect imaging is then performed using a frequency-domain cross-correlation imaging condition, followed by stacking over frequency and normalization. Validation experiments were conducted on an artificially manufactured vertical crack in a 7075 aluminum alloy specimen. The results indicate that, relative to conventional RTM, the proposed method reduces crack tip dominance and enhances the relative visibility and continuity of crack flanks. Compared with conventional RTM, the peak imaging amplitude increases by 22.44%, and the amplitude at a depth of 6.8 mm is enhanced by 24.39%. In addition, the proposed method outperforms the total focusing method (TFM) in crack profile continuity and the relative visibility of crack flanks. The results confirm that incorporating element directivity correction into frequency-domain RTM mitigates depth-dependent amplitude imbalance and restores crack flank visibility, thereby improving the reliability of crack defect characterization in ultrasonic NDT.

Chen, Si, Zhang, Yifeng, Ma, Tengfei, Xu, Zheng, Jiang, Jiansheng, Gao, Jiaqi

Research on Planting Concrete Preparation and Alkali Reduction Technology

2026-99-1518

9/11/2026

Planting concrete has drawn much attention due to its great potential in highway slope protection and ecological restoration. However, its practical application has been limited as its highly alkaline environment imposes severe restrictions on the germination of plant seeds and the growth of seedlings. To address this key issue, this paper conducted a systematic study on planting concrete preparation and alkali reduction technology. First, planting concrete samples that meet the basic physical and mechanical property requirements are prepared by optimizing the raw material ratio, mixing, molding, and curing processes. On this basis, the post-molding concrete samples are soaked in calcium superphosphate solution, so that the phosphate ions in it can have chemical reactions with the free calcium hydroxide in the concrete to make insoluble calcium phosphate salts, thus realizing chemical alkali reduction.

Liu, Ying, Yang, Wanting, Ma, Lijie

Study on Life Cycle Carbon Emissions of Light Commercial Vehicles

2026-99-1539

9/11/2026

In alignment with China’s national strategic objectives of “carbon peaking and carbon neutrality”, this study aims to pinpoint key greenhouse gas emission sources across the full life cycle of light commercial vehicles. A specific model of gasoline-powered truck is selected as the research subject for this investigation. Using a Life Cycle Assessment (LCA) framework and strictly following relevant international and national standards, this study constructs a three-stage accounting model covering the “raw material– manufacturing–use” process. This model quantifies the vehicle’s carbon emissions across all life stages and provides a detailed breakdown of their composition. Over 90% of the truck’s total carbon footprint stems from its use phase alone, highlighting this stage as the primary emission source. Within the use phase, the well-to-wheel emissions of gasoline are the main emission source. During the materials acquisition and processing stage, the smelting processes of steel and aluminum (including aluminum alloys) are the primary contributors to carbon emissions. The findings of this study can provide data support and technical references for commercial vehicle enterprises in low-carbon product design, green supply chain management, and the formulation of industry carbon emission standards.

Hu, Xiaona, Li, Jing, Chen, Ke, Cui, Chen

Numerical Investigation of In-Plane Antisymmetric Failure Modes and Load-Carrying Mechanisms of Steel Portal Piers

2026-99-1594

9/11/2026

A nonlinear finite element model was applied to study the in-plane instability of steel portal piers, in which initial geometric imperfections, welding residual stresses, and material nonlinearity were considered. The modeling procedure was compared with experimental results from box-section members, and consistent tendencies in load level and deformation evolution were observed. In the numerical analyses, the initial elastic buckling configuration exhibited an in-plane antisymmetric form. As loading continued beyond the elastic range, this deformation pattern persisted. With further loading, the deformation remained purely axial while combining compression with bending. During this stage, plastic hinges appeared near the column tops, while lateral displacement became clearly observable. Comparison models with different geometric proportions show that variations in the span-to-height ratio and the beam–column stiffness ratio influence how instability develops and where plastic deformation tends to localize. From a design perspective, these trends can be considered when distinguishing instability characteristics and selecting stiffness proportions between beams and piers.

Li, Jie, Shangguan, Bing, Cheng, Zhangxu, Ruan, Furong, Bai, Fan

Numerical Simulation Study on Borehole Wall Stability of Ultra-Large Diameter Deep Bored Piles in Thick Sand Strata

2026-99-1582

9/11/2026

Taking the newly constructed Maanshan Yangtze River Highway-Railway Dual-Purpose Bridge — a three-tower steel truss cable-stayed bridge with two main spans of 1120 meters — as the research object, this study systematically explores the influencing factors and evolutionary characteristics of hole wall stability for large-diameter bored piles in thick sand layers. The research results reveal the following mechanisms: with the expansion of pile diameter, the hole wall generates greater deflection, the soil’s internal arch effect is gradually attenuated, soil cohesion decreases, and the plastic zone of the soil surrounding the pile shows a tendency of outward extension, collectively increasing the susceptibility to hole collapse. To maintain hole wall stability, the resultant force of the internal circular arch support and mud pressure must exceed or equal the total lateral pressure, including active earth pressure, formation water pressure, and ground surcharge-induced lateral pressure. Notably, soil shear strength and mud relative density are two dominant factors controlling hole wall stability, and a positive correlation exists between these two parameters and stability. Specifically, a mud relative density range of 1.15–1.25 is recommended for practical construction. These findings offer valuable technical references for the design and construction of similar large-diameter bored pile projects in thick sand layers.

Ye, Tao, Wang, Ruyi

Intelligent Mold Library System for Copper Tube Drawing Process

2026-99-1108

9/11/2026

With the continuous and in-depth advancement of automotive lightweighting, the quality issues of automotive components have become increasingly prominent. Copper tubes, as an important component of automotive air conditioners, also need to ensure their quality level. In the production process of copper tubes, the multi- pass moving core head disc drawing process is one of the commonly used processing techniques. The relevant drawing dies determine the drawing effect and the quality of the finished copper tubes, so it is necessary to make a reasonable combination of drawing dies. At present, many copper tube processing enterprises overly rely on manual experience for mold matching work. Moreover, mold inventory information, usage records of matching molds, and mold size measurements are all completed by different operators. The operation procedures are not standardized, the standardization of mold matching operations is insufficient, there are too many uncertain factors, and the degree of human influence is too high. The intelligent mold library system for copper tube drawing process is designed to address the problems of weak stability, poor reproducibility, and insufficient precision in the existing manual mold matching. It facilitates accurate computation and control of process parameters. Compared with the estimation and rough adjustment based on manual experience, it can more accurately achieve the best parameter combination required by the process, thereby improving product quality and production efficiency. By integrating the mold matching methods of drawing pass process parameters such as the double decreasing method, the minimum pass method, the empirical pass method, the ZBL method, and the KD-KS coefficient method, and combining the inventory information in the system, it is ensured that the mold matching scheme generated by the algorithm is the best one, thereby improving the production level of the production process.

Yue, Fengli, Meng, Dezhi, Cui, Haitao, Zhang, Jiakun, Sun, Hongyun

Data-Driven Design of Copper Tube Drawing Algorithm for Automotive Air Conditioning Systems

2026-99-1110

9/11/2026

As a critical component in thermal management systems, copper tubes are widely used in automotive radiators, condensers, and other parts. In copper tube production, the drawing process is essential for achieving target dimensions and performance specifications. However, as the copper tube industry evolves, nowadays manual drawing process design and traditional drawing algorithms struggle to meet increasingly diverse finished product specifications and complex manufacturing requirements. To address this issue, this study developed an intelligent drawing process design algorithm suitable for automotive copper tube production. This algorithm builds upon existing drawing without plug algorithms, floating plug drawing algorithms, and manually compiled drawing process sheets. It first learns the fundamental principles of drawing without plug algorithms, then derives the relationship between wall thickness changes before and after drawing using mathematical formulas. Subsequently, by analyzing the enterprise’s existing 297 drawing process sheets, the design principles of the drawing without plug algorithm were extracted. This established the number and positioning of required drawing without plug processes within different drawing procedures as the design principles for drawing without plug. Then, using the ‘Double decrement method’ from the floating plug drawing algorithm as an example and integrating the design principles of drawing without plug processes, we developed an intelligent drawing process design algorithm suitable for automotive copper tube production. Furthermore, we selected a typical drawing process sheet for comparison. Through comparative analysis of key parameters such as processing rate and relative wall thickness reduction coefficient, we validated that this algorithm yields more rational results compared to traditional methods. Utilizing this algorithm not only significantly reduces the workload for drawing process designers but also produces more optimal drawing process design outcomes. Compared to other floating plug drawing algorithms, this algorithm also demonstrates greater universality.

Yue, Fengli, Zhang, Jiakun, Liu, Jinsong, Meng, Dezhi

Aluminum Alloy, Sheet and Plate, 4.4Cu - 1.5Mg - 0.60Mn (2024; -T3 Flat Sheet, -T351 Plate), Solution Heat Treated

AMS4037S (Current)

9/10/2026

This specification covers an aluminum alloy in the form of sheet and plate from 0.008 to 4.000 inches (0.20 to 101.60 mm) in thickness, inclusive (see 8.5).

AMS D Nonferrous Alloys Committee

Steel, Corrosion- and Heat-Resistant, Bars, Wire, Forgings, Forging and Ring Stock, Mechanical Tubing, and Rings, 12Cr (410 MOD), Ferrite Controlled, Annealed, Consumable Electrode Melted

AMS5611H (Current)

9/10/2026

This specification covers a premium aircraft-quality, corrosion- and heat-resistant steel in the form of bars, wire, forgings, mechanical tubing, flash-welded rings, and stock for forging or flash-welded rings.

AMS F Corrosion and Heat Resistant Alloys Committee

Steel, Bars, Forgings, Mechanical Tubing, and Forging Stock, 1.45Cr (0.93 - 1.05C) (SAE 52100), Aircraft Quality For Bearing Applications

AMS6440U (Current)

9/10/2026

This specification covers a low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.

AMS E Carbon and Low Alloy Steels Committee

Steel Bars, Forgings, Mechanical Tubing and Forging Stock 1.75Cr - 4.0Ni - 0.5Mo - (0.35 - 0.40C) Premium Aircraft Quality Consumable Electrode Vacuum Remelted

AMS6551B (Current)

9/10/2026

This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.

AMS E Carbon and Low Alloy Steels Committee

Steel Bars, Forgings, Mechanical Tubing and Forging Stock, 1.0Cr - 3.2Ni - 0.2Mo (0.12 - 0.17C) (ISO 14NiCrMo1304), Premium Aircraft-Quality, Double Vacuum Melted

AMS6549B (Current)

9/10/2026

This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.

AMS E Carbon and Low Alloy Steels Committee

Steel, Corrosion-Resistant, Bars, Wire, Forging, and Forging Stock, 13Cr (0.30-0.40C) (420), Annealed

AMS5621J (Current)

9/10/2026

This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, and forging stock.

AMS F Corrosion and Heat Resistant Alloys Committee

Steel, Corrosion- and Heat-Resistant, Bars, Wire, Forgings, Mechanical Tubing, Rings, and Forging Stock, 18Cr - 10Ni - 0.40Ti (SAE 321), Solution Heat Treated

AMS5645U (Current)

9/10/2026

This specification covers a corrosion- and heat-resistant steel in the form of forgings, wire, bars, mechanical tubing, flash-welded rings, and stock of any size for forging or flash-welded rings.

AMS F Corrosion and Heat Resistant Alloys Committee

Cobalt Alloy, Corrosion- and Heat-Resistant, Investment Castings, 60Co - 29Cr - 4.5W (Stellite® 6), As Cast

AMS5387G (Current)

9/10/2026

This specification covers a corrosion- and heat-resistant cobalt alloy in the form of investment castings.

AMS F Corrosion and Heat Resistant Alloys Committee

BEARING, BALL, AIRFRAME, ANTIFRICTION, HEAVY DUTY

AS27640F (Current)

9/9/2026

ACBG Rolling Element Bearing Committee

Titanium Alloy, Investment Castings 6Al - 4V, 130 UTS, 120 YS,6% EL, Hot Isostatically Pressed, Anneal Optional or When Specified

AMS4985F (Current)

9/9/2026

This specification covers a titanium alloy in the form of investment castings (see 8.6).

AMS G Titanium and Refractory Metals Committee

Compound, Corrosion-Preventive, Thin Film, Fingerprint Removing

AMS3065J (Current)

9/9/2026

This specification covers corrosion-preventive organic substances dissolved or emulsified in a volatile solvent and supplied in the form of a ready-to-use liquid.

AMS B Finishes Processes and Fluids Committee

Copper-Nickel-Tin Alloy, Bars and Rods, 77Cu - 15Ni - 8Sn, Solution Annealed, Cold Finished, and Spinodal Hardened (TX TS)

AMS4597B (Current)

9/9/2026

This specification covers a copper-nickel-tin alloy in the form of bars and rods up to 3.25 inches (83 mm) in nominal thickness (see 8.7).

AMS D Nonferrous Alloys Committee

Laser Peening

AMS2546B (Current)

9/9/2026

This specification covers the requirements for computer-controlled laser peening of metal part surfaces to induce residual compressive stresses at and beneath the surface.

AMS B Finishes Processes and Fluids Committee

Johnson-Cook Model Calibration of 10# Steel and Dynamic Mechanical Behavior Analysis under High Strain Rates

2026-99-1201

9/4/2026

As a typical material for fragmentation warheads, the mechanical behavior and ballistic penetration performance of 10# steel are critical for assessing warhead lethality. To characterize the dynamic response of 10# steel, systematic experiments were conducted, including quasi-static tensile tests, split-Hopkinson tensile bar tests, and thermal softening measurements. A = 505.46 MPa, B = 292.84 MPa, n = 0.335, C = 0.0343, and m = 1.213 are the calibrated Johnson–Cook parameters. Bridgman-corrected notched tensile tests determined damage parameters D1 to D4: 0.065, 0.746, −0.646, and 0.031). A study of its constitutive behavior shows that the strength of 10# steel increases with stress triaxiality and strain rate, whereas increasing temperature enhances ductility and reduces strength. Finite element software was updated to include the calibrated parameters to develop a material model for ballistic impact simulation. When compared with the ballistic penetration test results obtained using a 14.5 mm projectile, the simulated residual velocities show less than 5% deviation from the measured values. 3D scanning reveals that fragment sizes in experimental data differ by under 10% from simulation predictions. This work enables precise numerical simulations for warhead fragmentation prediction and lightweight armor design.

Tian, Yumo, Zhang, Longhui, An, Fengjiang, Feng, Bo

Molecular Dynamics Simulations of Microstructural Evolution in Pure Titanium under Laser Shock Peening

2026-99-1285

9/4/2026

Impacts of laser shock peening (LSP) on the evolution characteristics of microstructure in commercially pure α-phase titanium (α-Ti) are explored by molecular dynamics (MD) simulations of high strain-rate compression. The EAM potential (Zhou potential) is selected for its ability to capture the evolution of microstructures. Considering the LSP-induced peak plasma pressure, the strain rate during the simulated shock compression process is set at 10^9 s-1 to replicate the LSP process. The stress-strain curve of the α-Ti under high strain-rate compression is obtained. The maximum equivalent stress reaches 3.6 GPa, consistent with the theoretically calculated value. The simulation results reveal that mechanical twins (MTs) are activated at a strain of 3%. The number of mechanical twins increases and eventually stabilizes, forming a network structure throughout the grains. In the meantime, numerous partial dislocations are generated adjacent to the grain boundaries. The dislocation density also increases with strain and dislocation reactions occur. Moreover, grain refinement is identified. The grain size is refined from the initial ~ 8 nm to ~ 4 nm in the polycrystalline α-Ti. Twinning, together with dislocation-mediated plasticity, drives the refinement of grain size. Gradients of twin density, dislocation density, and grain size density are induced by LSP on the surface of α-Ti. This study comprehensively investigates how LSP influences the evolution of microstructures by MD simulations. It develops an innovative numerical strategy that offers a foundation for elucidating the underlying mechanisms of LSP.

Zhao, Congshan, Zhang, Linbing, Xu, Yidi, He, Jianye, Fang, Jing, Li, Zezhou, Ruestes, Carlos J., Cheng, Xingwang

Formation Characteristics of Non-Tangential Arc-Cone Tantalum-Tungsten Alloy Liner EFP

2026-99-1202

9/4/2026

KIKORiRoαiαoδ

Zhu, Mayuezhen, Li, Mei, Jiang, Jianwei, Men, Jianbing, Wang, Shuyou

W60(FeCrNi2.5) Alloy with High Strength and High Adiabatic Shear Band Sensitivity

2026-99-1243

9/4/2026

To meet the high-performance requirement of tungsten heavy alloys in kinetic energy penetrators under extreme dynamic loading conditions, high strength and high adiabatic shear band (ASB) sensitivity are essential. The formation and evolution of ASB during the penetration process directly dominate penetration capability of tungsten heavy alloys (WHAs). However, traditional WHA (93W) exhibits relatively low strength and adiabatic shear band insensitivity, which limits its applications in advanced kinetic energy penetrators. This study prepared W60(FeCrNi2.5) alloy by means of spark plasma sintering with 1~3 μm powders. The sintered alloy exhibits outstanding mechanical properties at quasi-static (0.001 s-1) and dynamic (4000 s-1) strain rates. Its yield strengths reach 1.5 GPa and 2.7 GPa respectively, manifesting a notable strain rate strengthening behavior. Dynamic compression tests indicate that the alloy generates ASB with a width of ~8 μm. Within the ASB, the body-centered cubic (BCC) phase is elongated to nanofibers under shear stress, and fine W particles are generated as a result of grain debonding in nanofibers. Meanwhile, the grains of the face-centered cubic (FCC) phase are disintegrated into subgrains due to dislocation pile-ups at subgrain boundaries, and new equiaxed grains are formed through subgrain boundaries rotation. The calculated adiabatic temperature elevation inside the ASB of this alloy reaches a maximum of 1315 K under 4000 s-1. Notably, its ASB sensitivity coefficient reaches 20.8, while that of the 93W alloy is 1.02. Thus, it achieves a favorable combination of high strength and high adiabatic shear band sensitivity, which offers meaningful references for advanced kinetic energy penetrator materials.

Lin, Jingchen, He, Jianye, Wang, Qiang, Wu, Shanghao, Zhang, Linbing, Ruestes, Carlos J., Li, Zezhou, Zhang, Zhaohui, Zhang, Fan, Wang, Lin, Cheng, Xingwang

An Experimental and Numerical Study on the Optimization of Quasi-static Energy Absorption Performance in Aluminum Alloy Thin-walled Tubes with Varied Notch Configurations

2026-99-1255

9/4/2026

Aluminum alloy thin-walled tubular parts play an important role in the energy absorbing elements of automotive passive safety. The number of geometry-trigger based notches is a factor in alleviate the initial force peak and shift the progressive buckling mode. However, until now, only limited work has been reported considering multiple notches. It is hard to clearly understand the impacts of the number of triggers on the buckling behavior and thresholds. Here, a mixture of quasi-static axial compression testing with high-fidelity finite element simulations is used to explore the influence of elliptical perforation number on AA6061-T6 tube crushing behaviour. For the first time, it is demonstrated that increasing the perforations leads to non-monotonic buckling evolution: from symmetry increasing → asymmetrical instability → optimal re-symmetrization → excessive weakening. We observe this transition from isolated holes to a collective “weakening hoop” controlling symmetric buckling as the number of holes increases. Our results give optima for separate objectives; T6 offers the best overall crashworthiness (45.2% less maximum force), with the other measures showing T4 with the best stiffness. We determine quantitative relationships between the number of holes and corresponding performance metrics. This gives practical design criteria for the design of energy absorbers.

Guo, Zifa, Jin, Ming

Synergistic Optimization of Geometry and Properties of Al-CF/PEEK Hybrid Curved Beams Formed via One-Step Hot Stamping

2026-99-1209

9/4/2026

Fiber metal laminates (FMLs) are widely used in high-end transportation equipment due to their excellent lightweight characteristics and high strength. Among various fabrication methods, the one-step hot stamping process offers an advanced and efficient approach for manufacturing FML hybrid components. The critical process parameters of this method have a decisive impact on the final component's mechanical properties and geometric accuracy. In this study, Al-CF/PEEK hybrid curved beam components consisting of 6061-T6 aluminum alloy, PEEK films, and CF/PEEK prepregs were fabricated using the one-step hot stamping forming process. Mechanical testing, digital image correlation (DIC) technique, and scanning electron microscopy (SEM) were employed to investigate the effects of forming process parameters (forming pressure and stamping speed) on the mechanical properties and geometric accuracy of the hybrid components. Results indicate that stamping speed has minimal impact on component thickness but significantly affects the spring-in angle and mechanical properties. As the stamping speed increases, the spring-in angle decreases; however, mechanical strength also declines. Higher forming pressure results in reduced spring-in angles, with the smallest value (0.73°) observed at a pressure of 4 MPa. However, excessive pressure introduced interface damage, causing mechanical properties to deteriorate after a certain threshold. Optimal performance was achieved at a stamping speed of 10 mm/s and a forming pressure of 3 MPa, yielding a strength of 244.82 N·mm/mm and a critical fracture energy of 5.002 N·m, along with high geometric accuracy. These findings offer valuable guidance for optimizing the process.

Deng, Yulong, Li, Yibo, Huang, Minghui, Dong, Lei, Lu, Yan, Peng, Jingquan

Detection of Pipe Surface Coatings on Ultrasonic Guided Wave Propagation

2026-99-1215

9/4/2026

Coating the surface of pipelines is one of the most crucial and effective methods for inhibiting corrosion and prolonging the operational lifespan of pipelines. The coating acts as a protective shield that isolates the pipeline metal from external corrosive environments. However, once the coating begins to peel off or deteriorate due to aging, mechanical damage, or environmental factors, the exposed metal surface becomes highly susceptible to corrosion. Statistics indicate that over 50% of external corrosion failures in pipelines are directly associated with coating defects. Despite the critical importance of coating integrity, research on the interaction between surface coatings and nondestructive testing methods—particularly ultrasonic guided wave techniques—has remained relatively limited in recent years. In this study, the impact of surface coatings on the propagation behaviors of ultrasonic guided waves in pipeline systems was systematically investigated. Coal tar pitch, a commonly used and cost-effective coating material, was applied to steel pipeline specimens with varying coating lengths. The attenuation rate of the guided wave signal amplitude was measured under different coating conditions to analyze the relationship between coating parameters and acoustic energy loss. The experimental results reveal that the coating significantly affects guided wave propagation, especially in terms of signal attenuation and boundary reflection. Furthermore, the study reveals that ultrasonical guided waves possess strong sensitivity to coating discontinuities and can accurately locate coating boundaries. These findings confirm the potential of guided wave technology for early detection of coating defects and quantitative evaluation of coating adhesion. Moreover, the outcomes provide useful insight for other transportation and aerospace structures that employ multilayer coatings or protective films, such as aircraft pipelines and composite fuselage components, where similar material interfaces and inspection challenges exist. This research provides theoretical and experimental references for improving the reliability of pipeline health status detection.

Xiao, Tianyi, Li, Bing

Experimental Verification of Chatter Optimization for Deep Small Hole Micro-Boring Based on 05Cr17Ni4Cu4Nb

2026-99-1273

9/4/2026

Aircraft engine parts are extremely precise, and for deep, small-hole machining of the stainless steel 05Cr17Ni4Cu4Nb valve seat, the quality and sealing of the parts machined with current machining parameters are poor. This greatly affects production efficiency and quality. This article takes the optimization of the three elements of cutting as the starting point, uses the orthogonal experimental method to study which force most affects machining quality in the three directions of boring force, and selects the appropriate three elements of cutting to reduce cutting force. And analyzed the simulated chip shapes before and after optimization, and finally verified the optimization effect through the instrument equipment. A micro three- axis accelerometer was used to conduct machining experiments on deep small holes with cutting parameters before and after optimization. After optimization of cutting parameters, the tool's maximum axial deformation showed a reduction of about 51.60%, a reduction of approximately 58.75% was achieved in the maximum radial deformation, the maximum tangential deformation exhibited a decline of about 45.17%, and the peak overall deformation was reduced by approximately 50.66%. Compared with the pre-optimized state, using optimized cutting parameters to machine deep small holes resulted in a 72.31% reduction in the tool's axial acceleration, the radial acceleration by 63.36%, and the tangential acceleration by 71.68%, the tangential force by 65.29%, the axial force by 27.93%, and the radial force by 31.16%. Effectively reducing tool chatter and lowering chatter amplitude led to the disappearance of surface vibration patterns on the machined parts.

Liu, Xinwei, Shi, Guangfeng, Zhou, Yuning, Gao, Jinglong

Control of Heat Treatment Deformation in Thin-Walled Pipe Fittings and Optimization of Turning Processes

2026-99-1300

9/4/2026

A certain component features an overall thin-walled structure with a wall thickness less than 1 mm, manufactured from high-strength martensitic precipitation-hardening steel. This part demands extremely stringent dimensional accuracy, with circumferential wall thickness variation not exceeding 0.006 mm, making it a typical high- precision thin-walled component. To ensure component performance and material utilization, the primary forming processes include spin forming, solution heat treatment, and multiple turning operations. During actual machining, martensitic precipitation-hardening steel exhibits significant microstructural stress relaxation and uneven cooling after solution heat treatment, leading to substantial part deformation. This makes it difficult to control subsequent machining dimensions within tolerance limits. Additionally, conventional clamping methods during multi-pass turning operations often cause uneven stress distribution on components during processing, frequently resulting in dimensional deviations that severely impact finished product yield rates. To address this challenge, this study systematically developed specialized tooling design and optimized turning processes tailored to the structural characteristics and deformation mechanisms of these thin-walled tube blanks. Simultaneously, a gap-free turning fixture with uniform expansion and clamping capabilities was developed. Combined with optimized machining parameters during the turning stage, this significantly improved stress distribution during processing, preventing further deformation caused by localized stress concentration. Test results indicate that after process optimization, the overall machining accuracy of this component improved by approximately 70% compared to the original process. Critical geometric tolerances showed significant enhancement, with roundness error consistently controlled within 0.30 mm and diameter dimensional consistency markedly improved. These measures not only successfully addressed deformation control challenges during heat treatment and machining of thin-walled parts but also provided a viable process solution and technical reference for precision manufacturing of similar high- difficulty, high-precision components.

Kou, Yue, Zhao, Honglian

Multi-Scale Investigation of Burn-Through Mechanisms during In-Service Welding of Pipeline Steel

2026-99-0409

8/28/2026

The core challenge of in-service welding repair of oil and gas pipelines is the risk control of burn-through. Current research primarily focuses on macroscopic phenomena, lacking a systematic multi-scale analysis of burn-through mechanisms and their dynamic evolution. Existing criteria are primarily based on qualitative experience, and widely accepted quantitative safety assessment standards have yet to be established. Furthermore, insufficient understanding of multi-scale damage failure mechanisms and weak theoretical foundations have become bottlenecks in this field. This study targets X65 pipeline steel and combines in-service welding experiments with in-situ scanning electron microscope tensile tests to elucidate the formation mechanism of burn-through from a multi- scale perspective. The results show that during in-service welding, the remaining wall thickness of the pipeline continuously decreases with the welding process, ultimately resulting in burn-through holes. On one hand, the welding arc drives the expansion of the hole; on the other hand, the internal pressure of the medium further enlarges the hole, leading to the expulsion of water and rapid pressure loss in the pipeline. Notably, the fusion zone behind the maximum melt depth is subject to high temperatures, which reduces strength and degrades plasticity, exhibiting significant plastic strain, making it a high-risk area for burn-through instability. Before instability occurs, this region shows evident grain coalescence, with plastic deformation primarily occurring through dislocation slip; when the difficulty of activating slip systems increases, twinning deformation may be induced, and large twin grains rarely develop cracks. Strain concentration and crack initiation are more likely to occur between grains with significant orientation differences.

Wang, Bangyu, Qiao, YingJie, Li, Dong, Xu, ShiHang

Effects of Binary-Shielding-Gas GTAW on the Microstructure and Mechanical Properties of Inconel 690 Welded Joints

2026-99-0418

8/28/2026

This study produced autogenous gas tungsten arc welds in 6 mm thick Inconel 690 plates using Ar-He shielding gas. The influence of helium content on arc characteristics, molten-pool geometry, microstructure, and mechanical properties was investigated systematically. With increasing helium fraction, the arc adopts a flattened, fan-shaped profile, leading to significantly greater penetration and bead width, accompanied by higher arc voltage and heat input. The weld-metal grain size is refined by up to 13.25%, while the solidification grain-boundary morphology shifts from cellular to a mixed equiaxed/cellular structure, and the fraction of high-angle grain boundaries increases. These microstructural changes reduce the ultimate tensile strength by a maximum of 12.21% and the elongation by 3.23%. Balancing weld quality and mechanical performance, gas mixtures of 60% Ar-40% He or 40% Ar-60% He are recommended as optimal shielding compositions for GTAW of Inconel 690.

Wang, Zhanfang, Li, Zhenlong, Lei, Jiaxuan, Chi, Houchao, Niu, Ben, Jiang, Guoyan, Zhang, Xuanbin, He, Bing

Vinylene-Linked Covalent Organic Frameworks as Superior Photocatalysts for Hydrogen Evolution over Imine-Linked Counterparts

2026-99-0414

8/28/2026

The scheme of photocatalysis of water, a way of hydrogen generation as a clean, high-efficiency fuel source for aircraft and long-range transport systems has received considerable interest. The development of the covalent organic framework (COF) - derived materials for hydrogen evolution reaction (HER) has since become a research highlight. Compared to traditional methods, photocatalytic hydrogen evolution systems based on COFs can provide ways of generating hydrogen gas without depending upon noble metal catalysts, thereby enhancing the sustainability and prospects of this technology for future aerospace energy applications.In this work, two covalent organic frameworks (COFs) with distinct linkages—a vinylene-linked COF A (via Knoevenagel condensation) and an imine-linked COF B (via Schiff-base reaction)—were designed and synthesized to compare their performance in the photocatalystic hydrogen evolution reaction (HER). Structural and electrochemical characterizations confirmed that, despite lower crystallinity and specific surface area due to pore blockage, COF A exhibited a suitable band structure for photocatalysis and achieved an HER rate of 56 μmol h^–1 g^–1 under simulated sunlight. In contrast, COF B was ineffective. This study experimentally validates the superior photocatalytic potential of vinylene-linked COFs over imine-linked counterparts for HER, highlighting their potential as non-noble-metal catalysts for aerospace and transport-oriented fuel generation.

Cao, Yijie, Luo, Xin

Effect of Copper Valence and Content in Copper Red Glaze on Its Color Appearance

2026-99-0420

8/28/2026

Copper red glazes have received considerable attention due to their perfect decorative effects and vivid coloration. This paper selected four different formula copper red glazes with different colors of bright red, violet blue, dark red, and gray blue as the samples. Based on the analysis of the colorimeter, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscope (SEM), a possible coloration mechanism was proposed to explain the variation of glaze colors. The results indicated that the glaze layers were mainly composed of amorphous phases with few quartz diffraction peaks and mainly presented a granulous structure and phase separation. Increasing the content of CaO could cause color changes of the glaze due to the high ionic potential of calcium ions, which could form a unique feature in the glaze melt. In addition, a small amount of calcium phosphate could greatly change the color of the glaze. The phase separation structure of the blue samples was more obvious than that of the red samples, with a phase separation size of less than 100 nm. The formation of droplet phase separation structure in the glaze could lead to Rayleigh scattering and Mie scattering, which made the color of copper red glazes blue and opacified. Increasing the content of Cu0 and decreasing Cu+ could weaken the structural color, which contributes to a* value of the glaze changing from 26.93 to 22.93. At the same content of Cu0, the higher the ratio of Cu+ /Cu2+ is, the less a* value of the glaze is. Finally, the existence of CuSiO3 in the glaze could also make the blue color.