Browse Topic: Metals

Items (33,660)
This specification establishes the requirements for dyed anodic coatings on aluminum alloys
AMS B Finishes Processes and Fluids Committee
This specification covers an aluminum alloy in the form of hand forgings up to 5.000 inches (127.00 mm), inclusive, in nominal thickness at the time of heat treatment, procured to inch/pound dimensions (see 8.6
AMS D Nonferrous Alloys Committee
This specification covers a corrosion- and heat-resistant nickel alloy in the form of bars, forgings, flash-welded rings, and stock for forging or flash-welded rings
AMS F Corrosion and Heat Resistant Alloys Committee
ABSTRACT FeMnAlC alloys exhibit lower density (6.5-7.2 g/cm3) than traditional military steels (7.9 g/cm3) while maintaining similar energy absorption capabilities. Material substitutions in legacy systems must meet existing form/fit/function requirements, limiting opportunities for lightweighting of existing designs. This study examines production and material properties of thick plate with a nominal chemistry of 30% Mn, 9%Al and 1%C, in the wrought condition. Due to the high aluminum and carbon content, there are unique challenges to large scale (45+ ton heat) production versus typical armor steel chemistries. Lab-scale wrought and production material are characterized, comparing microstructure, and mechanical properties. Processing practices including teeming flux and rolling temperature are discussed. The high manganese content of this alloy presents challenges for welding and machining practices, such as limited compatibility of weld wires and substantial work hardening during
Sebeck, KatherineToppler, IanRogers, MattLimmer, KristaCheeseman, BryanHowell, RyanHerman, William
ABSTRACT The family of lightweight high Mn, high Al steels (FeMnAl) exhibit lower density (6.5-7.2 g/cm3) than traditional military steels (7.9 g/cm3). These alloys are precipitation hardened, with κ-carbide dominating hardening performance. This carbide has an E21 perovskite structure with a nominal composition of (Fe,Mn)3AlC. In the literature, a number of studies have examined the sensitivity of mechanical properties to changing a single element in the composition. However, the covariance of the major elements has not been systematically explored. In this study, a series of small ingots were prepared according to a two-factor design of experiments, in addition to analysis of previously generated compositions. Methods of measuring alloy composition will be discussed, along with aging kinetics and key mechanical properties. Citation: K. Sebeck, I. Toppler, K. Limmer, D. Field, D. Wagner, A. Gafner, “Compositional Sensitivity of High Mn, High Al Steels”, In Proceedings of the Ground
Sebeck, KatherineToppler, IanLimmer, KristaField, DanielWagner, DanielGafner, Alyssa
ABSTRACT V-shaped hulls for vehicles, to mitigate buried blast loads, are typically formed by bending plate. Such an approach was carried out in fabricating small test articles and testing them with buried-explosive blast load in Southwest Research Institute’s (SwRI) Landmine Test Fixture. During the experiments, detailed time dependent deflections were recorded over a wide area of the test article surface using the Dynamic Deformation Instrumentation System (DDIS). This information allowed detailed comparison with numerical simulations that were performed with LS-DYNA. Though in general there is good agreement on the deflection, in the specific location of the bends in the steel the agreement decreases in the lateral cross section. Computations performed with empirical blast loads developed by SwRI and by more computationally intensive ALE methods in LS-DYNA produced the same results. Computations performed in EPIC showed the same result. The metal plate was then bent numerically so
Walker, James D.Chocron, SidneyMoore, Thomas Z.Bradley, Joseph H.Carpenter, Alexander J.Weiss, CarlGerlach, Charles A.Grosch, Donald J.Grimm, MattBurguess, Victor W.
ABSTRACT A prescriptive qualification scheme was completed for Arc Directed Energy Deposition (DED) metal Additive Manufacturing (AM) processes for austenitic single-sided builds. Robotic arc DED AM qualification builds used stainless steel consumables with the gas metal arc welding - pulse (GMAW-P) process. A matrix of standard qualification builds were made to develop, evaluate, and recommend the preferred process qualification build schemes. The qualification scheme explored a range of heat inputs, deposit sizes, and deposition rates; and the effects of interpass temperature that can be a limiting productivity factor for robotic arc DED metal AM builds. The standard qualification builds evaluated the effects of thickness (thin and thick geometric build features) where the process deposit (heat input) and process build thermal features (preheat and interpass temperature) are controlled over smaller ranges. The builds were examined with both ultrasonic and radiographic inspection, and
Harwig, D.DMohr, W.Hovanec, S.Rettaliata, J.Hayleck, R.Handler, EFarren, J.
ABSTRACT This paper reviews research that has been conducted to develop inductively assisted localized hot forming bending technologies, and to use standardized welding tests to assess the practicality and potential benefits of adopting stainless based consumables to weld both existing and evolving armor alloys. For the titanium alloy Ti6Al4V it was determined that warming the plate to circa 600°F would improve the materials ductility (as measured by reduction of area) from ~18 to 40% without exposing the material to a temperature at which atmospheric contamination would be significantly deleterious. For the commercial alloy BB and class 1 armor alloy it was found that there was little effect on the charpy impact toughness and the proof strength as a result of processing at 900 °F with either air cool or water quench and there was an added benefit of lower residual stresses in the finished bends compared to cold formed bends. Heating “alloy BB” to 1600 °F followed by water quench
Lawmon, JohnAlexandrov, BoianDuffey., MatthewNgan., Tiffany
ABSTRACT A newly developed structural adhesive demonstrates a unique combination of high strength (43 ± 2 MPa) and displacement (4.7 ± 1.2 mm) in aluminum lap joint testing. Bulk material characterization of the prototype adhesive reveals its extreme ductility, with nearly 80% shear strain before failure and a 2.5-fold increase in strain energy density as compared to commercial structural adhesives. The prototype adhesive is found to maintain 67 to 82% of its initial strength under extreme environmental conditions, including at high temperatures (71°C), after high humidity (63°C hot water soak, 2 weeks), and after corrosive conditions (B117 salt spray, 1000 hours). The prototype structural adhesive is shown to also generate high strength bonds with multiple substrates, including steel, carbon fiber, and mixed material joints, while also providing galvanic isolation
Pollum, MarvinKriley, JosephNakajima, MasaTan, Kar TeanStalker, JeffreyFleischauer, RichardRearick, Brian
ABSTRACT The US Army TARDEC has been researching an alternative to current armor steel that is both tough, and light-weight. The studied alloy is based on the Fe-Mn-Al-C system. This study was conducted to investigate and quantify this alloy’s susceptibility to hot cracking phenomena related to casting and welding. Very little research has been done on general weldability of this alloy system, so the results of these tests will be compared to other high Mn steels, and alloys that have undergone cast pin tear testing. Testing will be conducted utilizing button melting tests, autogenous spot welds, and cast pin tear testing. The cast pin tear testing was conducted to measure this alloys susceptibility to weld solidification cracking. The spot welds were used to quantify the susceptibility of the weld heat affected zone (HAZ) to liquation cracking, as well as to observe the solidification structure of the fusion zone. The testing results showed that the FeMnAl system in its current form
Evans, WilliamRamirez, Antonio J.Sebeck, Katherine
ABSTRACT This paper addresses candidate technologies for attaching steels to selected lightweight materials. Materials of interest here include aluminum and titanium alloys. Metallurgical challenges for the aluminum-to-steel and titanium-to-steel combinations are first described, as well as paths to overcome these challenges. Specific joining approaches incorporating these paths are then outlined with examples for specific processes. For aluminum-to-steel joining, inertia, linear, and friction stir welding are investigated. Key elements of success included rapid thermal cycles and an appropriate topography on the steel surface. For titanium-to-steel joining, successful approaches incorporated thin refractory metal interlayers that prevented intimate contact of the parent metal species. Specific welding methods employed included resistance mash seam and upset welding. In both cases, the process provided both heat for joining and a relatively simple strain path that allowed significant
Gould, Jerry E.Eff, MichaelNamola, Kate
ABSTRACT As metallic parts are used, wear, fracture, galling, warpage, and other forms of obsolescence occur. When these issues progress beyond a predefined level, the parts are either replaced or repaired. Replacement leads to undesirable logistics requirements, especially for those parts requiring difficult-to-source, expensive and/or long-lead-time materials. Repair options are often limited due to strict performance requirements of the parts or concern over the quality of the repair. Two relatively new additive manufacturing (AM) process options exist to complete repairs, including repairs required in theater. Hybrid repair via metal AM followed by precision machining within a single setup offers unique repair options not previously available. Though somewhat limited with respect to the number of alloys currently tested, hybrid AM via directed energy deposition (i.e., powder sprayed into a laser-heated liquid metal pool) offers the possibility to quickly, economically and
Sabo, Kenneth M.Golesich, Brock T.Tims, Michael L.
ABSTRACT A bainite phase-based alloy and associated thermomechanical process were developed to produce (2.5 to over 5 cm) thick armor-grade steel with uniform through-thickness high hardness and strength. The alloy composition and the final-critical (austenite to bainite) isothermal transformation step were specifically designed to utilize a simple and versatile air-cool/quench method to keep a low upfront capital cost and to provide the ability to continuously control the cooling rate in real time, in order to produce maximum volume fraction of bainite phase, and promote uniformly distributed strength and hardness. Final thickness of 1.9 cm and 5.7 cm steel plates were fabricated for characterization, testing and evaluation and found to possess uniform through-thickness hardness between 53 to 55 HRC and dynamic compressive strength of up to 2 GPa
Chu, Henry S.Lillo, Thomas M.Anderson, Jeffrey A.Zagula, Thomas A.
ABSTRACT Results are presented from tests on a formulated 15W-40 mil-spec engine/transmission fluid to examine the impact of additives on improving its reliability and durability under extreme tribological conditions. A block-on-ring (BOR) configuration was used to measure the effect of five additives (an emulsion-based boric acid, tricresyl phosphate, particulate-based boron nitride, particulate-based MoS2, and particulate-based graphite) on the critical scuffing load as a function of additive concentration and time to scuff during oil-off tests (starved lubrication). A four-ball configuration was used to evaluate the impact of simulated engine grit/sand on the abrasive wear of steel as a function of grit size and loading. The results demonstrated that the additives increased the load for scuffing by 50 to 100% for the formulated oil and by 50 to 150% for the unformulated base fluid used in the formulated oil. Two of the additives (emulsion-based boric acid and tricresyl phosphate
Fenske, G. R.Ajayi, O. O.Erck, R. A.Lorenzo-Martin, C.Masoner, AshleyComfort, A. S.
ABSTRACT Flash® Bainite Processing employs rapid thermal cycling (<10s) to strengthen commercial off the shelf (COTS) steel sheet, plate, and tubing into Ultra Hard 600 Armor, High Hard 500 Armor, and advanced high strength steel (AHSS). In a continuous process, induction technology heats a narrow segment of the steel cross section in just seconds to atypically high temperature (1000-1300°C). Quenching substantially immediately follows. A report by Benet Labs and Picatinny Arsenal, investigating a less mature flash technology in 2011, surmised that the novel flash bainite process for steels has the potential to reduce cost and weight while also enhancing mechanical performance [1]. Receiving five financial grants, the US Dept of Energy has greatly matured flash technology in the last few years and its metallurgical understanding in collaboration with Oak Ridge National Lab and others. DOE has named Flash Bainite as the “SBIR Small Business of the Year” in May 2018 and awarded a Phase 3
Cola, Gary M
ABSTRACT The armor research and development community needs a more cost-effective, science-based approach to accelerate development of new alloys (and alloys never intended for ballistic protection) for armor applications, especially lightweight armor applications. Currently, the development and deployment of new armor alloys is based on an expert-based, trial-and-error process, which is both time-consuming and costly. This work demonstrates a systematic research approach to accelerate optimization of the thermomechanical processing (TMP) pathway, yielding optimal microstructure and maximum ballistic performance. Proof-of-principle is being performed on titanium alloy, Ti-10V-2Fe-3Al, and utilizes the Hydrawedge® unit of the Gleeble 3800 System (a servo-hydraulic thermomechanical testing device) to quickly evaluate mechanical properties and simulate rolling schedules on small samples. Resulting mechanical property and microstructure data are utilized in an artificial intelligence (AI
Lillo, ThomasChu, HenryAnderson, JeffreyWalleser, JasonBurguess, Victor
ABSTRACT Friction stir welding is a solid state joining technique in which no melting of the metals is involved. The technique is very attractive for aluminum alloys due to the low heat input involved in the process, which leads to improved mechanical properties as compared to conventional fusion welds. In this work, different aluminum series alloys were friction stir welded together. The aluminum alloys consisted of a solid solution/strain hardened aluminum alloy 5083-H131, and precipitation strengthened aluminum alloys 2139-T8 and aluminum 7085-T721. The joint combinations were aluminum alloys 5083-H131 to 7085-T721, aluminum alloys 2139-T8 to 7085-T721, and aluminum alloys 5083-H131 to 2139-T8. Their mechanical properties were analyzed and compared to base metal properties. Optical microscopy was used to analyze the grains in the welds. Good mixing of the different aluminum alloys was optically observed in all of the welds, which lead to good joint properties, opening the
Martinez, NelsonMcDonnell, Martin
ABSTRACT Most studies conducted on friction stir welded (FSW) Al alloys are on plates that are 2.5-7 mm thick. However, the U.S. Army utilizes materials that are 25 mm thick and greater for structure and armor. In order to properly apply FSW to Al-Cu-Mg-Ag alloys for use in next generation ground vehicles, data must be generated and available for model and simulation databases. One key type of data is the tensile-creep behavior of FSW AA 2139-T8. Creep is the time dependent, plastic deformation of a material under a constant load, usually observed at a constant temperature where T>0.3Tm. The objective of this study is to provide information regarding the tensile-creep behavior of the stir zone in comparison to the heat affected zone (HAZ) through the depth of the weld. The results from this research provide information on the effect of FSW processing on the microstructure and creep behavior. Pre- and post-deformation samples were analyzed via SEM and TEM and the results are discussed
Okeke, UchechiBoehlert, Carl
Related to traditional engineering materials, magnesium alloy-based composites have the potential for automobile applications and exhibit superior specific mechanical behavior. This study aims to synthesize the magnesium alloy (AZ61) composite configured with 0 wt%, 4 wt%, 8 wt%, and 12 wt% of silicon nitride micron particles, developed through a two-step stir-casting process under an argon environment. The synthesized cast AZ61 alloy matrix and its alloy embedded with 4 wt%, 8 wt%, and 12 wt% of Si3N4 are subjected to an abrasive water jet drilling/machining (AJWM) process under varied input sources such as the diameter of the drill (D), transverse speed rate (v), and composition of AZ61 composite sample. Influences of AJWM input sources on metal removal rate (MRR) and surface roughness (Ra) are calculated for identifying the optimum input source factors to attain the best output responses like maximum MRR and minimum Ra via analysis of variant (ANOVA) Taguchi route with L16 design
Venkatesh, R.
ABSTRACT Due to the recent fluctuations in the rare-earth magnet pricing and availability demands, switched reluctance machines (SRMs) have gained significant interest to be used in automotive and military applications. SRMs are known to have high power density/efficiency, low cost, easy manufacturability, wide constant power region, robust structure and high reliability. On the other hand, high acoustic noise and torque ripple have limited their wide spread usage in the past. This paper investigates the analyses, design and experimental verification of various acoustic noise reduction techniques for SRMs. The prototypes of 100 kW SRMs for military ground vehicles have been built with the implemented acoustic noise reduction techniques and were tested using a dynamometer special for electric and hybrid vehicle testing
Sozer, YilmazTylenda, JoshuaKutz, JohnWright, Ronnie L.
ABSTRACT This paper describes the results of work performed to assess the use of corrosion product for Digital Image Correlation (DIC) measurements. DIC was recently evaluated for its capability to measure contour, strain and deflection of metals using the corrosion product instead of a painted speckle pattern. The DIC system, consisting of two cameras with zoom lenses, was set up at an angle to the specimen, enabling both cameras to image multiple sides of a specimen simultaneously. This provides a more direct measurement of in-plane and out-of-plane deformation and strains. Aluminum and steel dogbones were placed in a salt spray chamber for up to 10 days. Contour measurements were then taken at various evaluation settings as an initial assessment of the use of the corrosion product for DIC measurements. Multiple tensile tests were then performed to assess the capability of using corrosion product for strain and deflection measurements while a material is under applied load. System
Sia, Bernard
ABSTRACT Survivability of a welded vehicle hull is directly tied to the performance of the grade of steel armor used. Selecting the highest performing grade of armor that can be welded into a specific location on a vehicle will improve survivability. While rolled homogeneous armor is the simplest to weld, challenges in welding high hard, and especially ultra high hard, are well known. Preventative measures to avoid weld cracking in vehicle structures can lead to increased costs during fabrication. Cracking of welds, both seen and unseen, in deployed vehicles directly impacts the survivability of the vehicle. Weld cracking during deployment further magnifies repair costs and leads to non-mission capable status. This analysis examines the weldability, ballistic/blast performance, and underlying metallurgy of Flash® Processed steels that have been tested by Army, Academia, and Industry. Citation: G. Cola, “Flash® 600 Ultra High Hard: Room-Temp ER120S-1 Weldability Tekken, H-Plate
Cola, Gary M
ABSTRACT Two relevant materials found in ground vehicle underbody armor/hull designs are Aluminum 2139-T8 and RHA Steel (Class I). These are 2 very important materials that need a thorough understanding of their high-strain rate behavior. The Johnson-Cook Deformation (JC-D) model at this time is the most preferred constitutive material model to utilize for high-strain (large deformation) blast simulations. The JC-D Model contains five empirically-based input parameters which can be determined traditionally through a series of uniaxial laboratory tests where each target parameter is isolated, while the remaining parameters are held constant. There are many criticisms and problems with this approach. The objective of this two part paper is to present and adopt a more accurate approach with less criticism to the determination of these five input parameters through both a sensitivity study to determine which input parameters are the most sensitive to a particular chosen response which in
Hause, TerrySheng, Jianping
ABSTRACT The Applied Science and Technology Research Organization of America (ASTRO America), Ingersoll Machine Tool (Ingersoll), MELD Manufacturing (MELD), Siemens Digital Industries (Siemens), The American Lightweight Materials Manufacturing Innovation Institute (ALMII), and the US Army CCDC-GVSC have partnered to show the feasibility of fabricating very large metal parts using a combination of additive and subtractive manufacturing technologies. The Army seeks new manufacturing technology to support supply chain strategy objectives to replace costly inventories and reduce lead times. While additive manufacturing (AM) has demonstrated production of metallic parts for military applications, the scale of these demonstrations is much smaller than required for large vehicle components and/or complete vehicle hull structures. Leveraging AM for large scale applications requires enhancements in the size, speed, and precision of the current commercially available state-of-the-art equipment
Rodriguez, Ricardo X.Wells, CorrineCarter, Robert H.LaLonde, Aaron D.Goffinski, Curtis W.Cox, Chase D.Bell, Tim S.Kott, Norbert J.Gorey, Jason S.Czech, Peter A.Hoffmann, KlausHolmes, Larry (LJ) R.
ABSTRACT Titanium and its alloys offer superior strength at a fraction of the weight of steel or nickel-based alloys. Some α-β titanium alloys such as Ti-6Al-4V have been widely used in laser powder bed fusion additive manufacturing applications due to the historical cast-wrought data sets and the availability of this alloy in powder form, however this alloy presents challenges during the laser-based printing process of components due to the high residual stress in the material. Alternative β-rich Ti alloys such ATI Titan 23™ can offer superior printability, lower residual stress, and higher mechanical properties than Ti-6Al-4V in additive manufacturing applications. This study covers the assessment of ATI Titan 23™ as an alternative printable Ti alloy and the resulting microstructure, mechanical properties, and residual stress of the printed material. Citation: Garcia-Avila, Foltz, “Low Distortion Titanium Alloy in Laser Powder Bed Fusion Additive Manufacturing System,” In Proceedings
Garcia-Avila, MatiasFoltz, John
ABSTRACT Cornerstone Research Group (CRG) developed a lithium metal (Li-metal) battery cell for military applications. Utilizing a Li-metal anode, high energy density cathode, and an advanced low-temperature fluorinated electrolyte, the cell was designed and developed to provide high-power and low temperature capabilities. The 1.5 Ah Li-metal pouch cell had a specific energy of 247 Wh/kg and was able to discharge at ultra-low temperatures (-57 °C). Moreover, the Li-metal cell demonstrated extremely high-power by fully discharging at 10 C while maintaining over 70% its initial capacity. To demonstrate the Li-metal cell’s utility for military vehicle use, CRG modeled the cell into the 6T battery platform. A novel module housing was designed to evenly apply compression to the Li-metal cells to improve cell performance. Based on these projections, the Li-metal 6T battery could have a capacity of 163 Ah with a specific energy of 179 Wh/kg. Citation: J. Hondred, F. Zalar, P. Nikolaev, B
Hondred, JohnZalar, FrankNikolaev, PashaHenslee, Brian
ABSTRACT Barriers to the introduction of composite materials for ground vehicle applications include material property selection and cost effective material processing. Advancements in processing of thermoplastic composites for use in applications for semi structural and structural applications have created opportunities in “Out of Autoclave” processing utilizing preconsolidated unidirectional reinforced tapes. Traditional tooling for the bending formation of high temperature reinforced structural thermoplastic laminates typically involves matched metal tooling consisting of steel or aluminum and are costly and heavy. In this research, a comparative analysis was performed to evaluate the use of a large scale 3D printed forming tool in comparison to a traditional metallic mold. Material processing considerations included the development of a technique for localized laminate heating to achieve optimized energy input in the forming process. Considerations in tooling development included
Erb, DavidDwyer, BenjaminRoy, JonathanYori, WilliamLopez-Anido, Roberto A.Smail, AndrewHart, Robert
ABSTRACT In order to defeat under body blast events and improve crew survivability, a monocoque aluminum cab structure has been designed as a drop on solution based on the current M1151A1 (HMMWV) chassis. The structure is comprised of all 5083-H131 Aluminum alloy armor plates with various thicknesses. The structure design consists of the following new features: (1) Robust joining design utilizing interlocking ballistic joints and mechanical interlocking features, (2) unique B-pillar gusset design connects roof & floor with B-pillar & tunnel, and (3) “Double V” underbody shaping design. The TARDEC designed, integrated & built vehicle achieved no crew core body injuries for a vehicle of this weight class and demonstrated meeting the crew survivability objective when subjected to a 2X blast during the live fire underbody blast tests. These efforts help to not only baseline light tactical vehicle capabilities, but also validate the possibility of meeting aggressive blast objectives for
Lee, Chu-HwaLacap, Demetrio M.Keller, Shawn J.
ABSTRACT TIAX is developing laminated prismatic lithium-ion (Li-ion) cell technology capable of rapid charging at low temperature (to -50 °C) to replace current lead-acid vehicle batteries. The novel cells are based on TIAX’s high energy, high power CAM-7 cathode material, high rate capability lithium titanate (LTO) anode material, and novel electrolyte formulation, and target cell-level energy content greater than 90 Wh/kg and 250 Wh/l. CAM-7 cathode material promises significant boost in power and run time of Li-Ion batteries for a wide range of DoD applications, and is now being commercialized by a separate company, CAMX Power, which is scaling up production in a 50 metric ton per year plant installed in Massachusetts
Ofer, DavidDalton-Castor, SharonNation, LeahPullen, AdrianRempel, JaneBarnett, BrianSriramulu, Suresh
ABSTRACT The demand for increased export power generation and ground vehicle electrification are escalating trends due to the warfighter’s expanding mission requirements. Today’s low-voltage alternators used in some fielded ground vehicle’s power systems supply up to 650ADC, or 18kW. Future demand for vehicle export power generation is expected to reach and exceed 100kW. A majority of electric machines capable of meeting this level of power generation rely on rare-earth elements such as Neodymium (Nd), Samarium (Sm), Dysprosium (Dy) and Terbium (Tb). Due to diminished reserves in the United States, availability abroad and price volatility, continued use of rare-earth permanent magnet materials may not be viable. The expanding demand for vehicle power is on a trajectory which surpasses the U.S. ability to reliably harvest or procure rare-earth magnet materials. As such, electric machine topologies that utilize zero rare-earth magnet materials are being considered for ISG (integrated
Riley, KatherineConway, ShanShanLee, Seong T.Jung, Yong-BaeZanardelli, Wesley G.Wright, Ronnie L.
ABSTRACT The foundation of the theory of functionally graded plates with simply supported edges, under a Friedlander explosive air-blast, are developed within the classical plate theory (CPT). Within the development of the theory, the two constituent phases, ceramic and metal, vary across the wall thickness according to a prescribed power law. The theory includes the geometrical nonlinearities, the dynamic effects, compressive tensile edge loadings, the damping effects, and thermal effects. The static and dynamic solutions are developed leveraging the use of a stress potential with the Extended-Galerkin method and the Runge-Kutta method. Validations with simpler cases within the specialized literature are shown. The analysis focuses on how to alleviate the effects of large deformations through proper material selection and the proper gradation of the constituent phases or materials
Hause, Terry
Abstract The United State Army employs several advanced armored combat vehicles, in a wide array of different environments, and applications. Armor steels are hard and are required to meet certain conditions to stay within the military’s specifications for armored steels. Vehicle armor is typically joined using arc welding methods. Joining via arc welding degrades armor material below specification, so alternate joining methods are being explored like Friction Stir Welding (FSW). FSW is a solid-state joining technique that utilizes a rotating pin to stir plasticized material and use a tool shoulder to forge the material into the joint. The advantages come from the reduction in peak temperature, an increase in mechanical performance, and a decrease in possible defects that occur. In this study FSW parameters were developed and used to weld Wrought Homogenous Armor (HRA) steel. The welds were subject to hardness indention, and metallographic analysis to observe an early prediction of
Evans, WilliamRamirez, AntonioMcDonnell, MartinEff, Mike
ABSTRACT Corrosion damage to military ground vehicles costs the U.S. Army around $1.6B per year. A large part of that cost is related to keeping vehicles like the Stryker at their full fighting capability. Corrosion damage has been a common finding on Stryker vehicles and even light corrosion damage, which often reaches 10% of the body thickness or more, can degrade its armor protection rating and require replacement. Recently, cold spray deposition has been shown to be capable of restoring the full ballistic resistance of corrosion damaged high hard steel armor panels. These repairs can be done on-vehicle in depot facilities, using mobile high-pressure cold spray systems. This repair capability can reduce the number of entire side, roof, and floor panels that need to be cut out and re-welded in, which is the only currently approved repair operation for corrosion damage that exceeds allowable depths. Citation: V.K. Champagne, C.A. Widener, A.T. Nardi, G.D. Ferguson, “Structural Repair
Champagne, Victor K.Widener, Christian A.Nardi, Aaron T.Ferguson, Gehn D.
ABSTRACT The U.S. Army - GVSC Materials Characterization and Failure Analysis team conducted a preliminary study in FY18 to address the issue of galvanic and pitting corrosion of U.S. Army ground vehicle system (GVS) structural surfaces. The objective of this study was to develop a permanent coating solution to supplement the existing corrosion protective coating of zinc rich primer and CARC paint, and extend the lifecycle of the armor. Twenty-five permanent, 0.1 inch layer, additively manufactured (AM) coated coupons of deposited Stellite 6 cobalt alloy on MIL-STD-46100 High Hard (HH) armor steel blocks were produced for cyclic testing using an un-optimized set of parameters. These coupons were subjected to a twenty-four week study in accelerated corrosive conditions of a fog spray chamber alongside primer-CARC coated and uncoated coupons. The resulting study showed no signs of pitting corrosion in the surface of the AM coated coupons, and minimal galvanic corrosion. Citation: I
Toppler, Ian JSchleh, Daniel CRomero, Claudio Gutierrez
ABSTRACT Laser powder bed fusion (L-PBF) of entire assemblies is not typically practical for technical and economic reasons. The build size limitations and high production costs of L-PBF make it competitive for smaller, highly complex components, while the less complex elements of an assembly are manufactured conventionally. This leads to scenarios that use L-PBF only where it’s beneficial and requires integration and joining to form the final product. Today the welding process requires complex welding fixtures and tack welds to ensure correct alignment and positioning of parts for repeatable results. In this paper, both L-PBF and milled weld preparations are presented to simplify Tungsten inert gas (TIG) welding of rotationally symmetrical geometries using integrated features for alignment and fixation. All welds produced in this study passed the highest evaluation group B according to DIN 5817. Citation: Ole Geisen, Tad Steinberg, “Microstructure analysis of TIG welded additively
Geisen, OleSteinberg, Tad
ABSTRACT The open-cell metal foams have an internal structure is a web of connected ligaments. Foams are made from pure or alloys of aluminum, nickel, steel, magnesium, titanium and copper. In addition to being light weight, the foams exhibit excellent stiffness-to-weight ratios. Some foams can be resilient materials in harsh environments and have high impact resistance. The foams have high conductivities and large surface area per unit volume. All of these attributes make metal foam an attractive core for heat exchange. For example, cooling of power electronics and for thermal management of ground vehicles can employ metal-foam designs. Numerical simulation of convection heat transfer due to airflow inside commercial aluminum foam is conducted in a commercial numerical package. For validation, actual air temperatures were locally measured inside heated commercial aluminum foam, and cooled by forced air flow using a specially-developed technique. Good agreement between the modeling and
Dukhan, NihadSULEIMAN, AHMED S.AL-RAMMAHI, MUNTADHER A.
ABSTRACT PPG formulates N-methyl pyrrolidone free (NMP−free) cathodes for Li−ion batteries capable of delivering sufficient power for automotive starting, lighting and ignition (SLI) as well as adequate charge capacity for powering auxiliary electronics. In this paper, NMP−free energy cathodes and power cathodes were formulated using developmental binders, and refinement of carbon/binder ratio and slurry mix procedure. Learnings from the energy and power cathode development were conceptually combined in the formulation of capacity enhanced power cathodes. These cathodes were evaluated electrochemically via power capability and rate capability testing in battery coin cells, as well as in 0.5 Ah multilayer pouch cells. Carbon content was found to be a critical factor in attaining high cold crank performance. This work represents significant steps toward potential commercialization of NMP−free cathode coated foil for Li−ion batteries. Citation: S. Esarey, A. Kizzie, C. Woodley, I. Matts
Esarey, Samuel L.Kizzie, AustinWoodley, ChristopherMatts, IanHellring, StuartZhou, ZhilianTerrago, Gina
ABSTRACT α-β titanium alloys are used in armor plate applications due to their capability to defend against ballistic threats while having a 40% lower density than steel. ATI 425® was developed as a cold-deformable alternative to Ti-6Al-4V with similar ballistic properties and improved blast performance owing to the alloy’s higher damage tolerance. ATI Titan 27™ is an evolutionary step forward on ATI 425® Alloy, and is being developed as a higher-performance titanium armor alloy owing to its greater than 10% improvement in strength with similar ductility and formability. Recent work has demonstrated a novel deformation mechanism that explains the improved cold deformation observed in both alloys over Ti-6Al-4V. This mechanism, a twinning of α-phase coinciding with slip in the β-phase, is unique among high-strength titanium alloys. Moreover, twinning is well known to be suppressed with high oxygen content, and ATI Titan 27™ Alloy has one of the highest oxygen targets across high
Foltz, JohnRuiz-Aparicio, LuisBerry, DavidPorter, Rick
ABSTRACT The U.S. Army identified the use of advanced materials in next generation combat vehicles design as a focal technology area of interest and urged industry to develop replacements that realize weight, sustainment, and cost savings. An initial life cycle analysis suggests that using Titanium road wheels as an alternative to legacy road wheels could cut 555.6 lbs. and reduce cost by $39,760.00 per each M-1 tank over a life cycle of 8,000 mi, resulting with $71.72 savings per each pound reduced. Secondary side-effects of the weight reduction achieved by the Titanium road wheels include improvements such as fuel economy, mobility, transportability, and risk-reduction in the inclusion of emerging metal matrix composite technologies in next generation combat vehicles. The paper recommends conducting field evaluation and considering the application of Titanium road wheels in the M-1/M-88, M-109, AMPV, MPF, OMFV, DLP/FDL, and RCV (H) platforms Citation: R. Paytan, R. Mazor, “Titanium
Paytan, RonnenMazor, Ronen
ABSTRACT With the increase in electric power on military ground vehicle platforms, electrically driven accessories are replacing existing hydraulic, belt, and gear-driven loads. Permanent Magnet Synchronous Machines (PMSM) are often selected to drive these accessories, and are under consideration for the main engine generator, due to their torque density and efficiency being among the highest available. To maximize the efficiency of a PMSM, accurate knowledge of its parameters is required across the entire operating range. Efficient control of the onboard electric drives will help reduce fuel consumption in the ground vehicle fleet. This paper presents the effects of iron saturation on the performance of a PMSM drive. Iron saturation depends on the amount of current injected into the motor and it restricts the amount of flux linkage that can be generated. PMSMs are controlled using a two axis space vector representation. Ideally, the control is decoupled, such that the flux linkage
Cintron-Rivera, Jorge G.Foster, Shanelle N.Zanardelli, Wesley G.Strangas, Elias G.
Aluminum alloys serve a critical role in the aerospace industry, accounting for a significant amount of commercial aircraft weight. Despite the growing use of composite materials, aluminum remains important in airframe construction due to its lightweight, cost-effectiveness, and high strength potential. Structural integrity is critical in modern engineering, necessitating early diagnosis and localization of damage. To detect the flaws, cracks, and cut-out in the structures, structural health monitoring (SHM) systems are essential, with non-destructive testing (NDT) methodologies playing critical roles. Among these technologies, ultrasonic guided wave testing (UGWT) has gained popularity because of its capacity to propagate over long distances and detect subsurface faults. This article investigates the use of UGWs to identify cut-outs in aluminum plates. The numerical investigation has been carried out using commercially available finite element software Abaqus. The ultrasonic lamb
Rajput, ArunPatil, Vaibhav KailasBhosale, AniketYadav, RiteshGhatge, AdityarajPandey, Anand Ji
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