Mitigation of urea deposit formation and improved ammonia production at low exhaust temperatures continues to be one of the most significant challenges for current generation SCR aftertreatment systems. Various technologies have been devised to alleviate these issues including: use of alternative reductant sources and thermal treatment of the urea-water solution (UWS) pre-injection. The objective of this work is to expand the knowledge base of a potential third option, which entails chemical modification of UWS by addition of titanium-based urea/isocyanic acid (HNCO) decomposition catalysts and/or surfactants to the fluid. Physical mixtures of urea and varying concentrations of ammonium titanyl oxalate (ATO), oxalic acid, and titanium dioxide (TiO2) were generated, and the differences in NH3 and CO2 production were evaluated. It was found that addition of 2.0 mol % ATO to urea increased CO2 production by 821 % and NH3 production by 96 % at temperatures ≤ 215 °C, indicating significantly enhanced hydrolysis of HNCO. Conversely, is was demonstrated that addition of oxalic acid or TiO2 to urea exhibited little effect on NH3 and CO2 production, indicating…

Titanium’s high strength-to-weight ratio and corrosion resistance makes it ideal for many aerospace applications, especially in heat critical zones. Superplastic Forming (SPF) can be used to form titanium into near-net, complex shapes without springback. The process uses a machined die where inert gas is applied uniformly to the metal sheet, forming the part into the die cavity. Standard titanium alpha-beta alloys, such as 6Al-4V, form at temperatures between 900 and 925ºC (1650-1700ºF). Recent efforts have demonstrated alloys that form at lower temperatures ranging between 760 and 790ºC (1400-1450ºF). Lowering the forming temperature reduces the amount of alpha case that forms on the part, which must be removed. This provides an opportunity of starting with a lower gauge material. Lower forming temperatures also limit the amount of oxidation and wear on the tool and increase the life of certain press components, such as heaters and platens. A variation of this process is SPF combined with Diffusion Bonding (SPF/DB) of two or more titanium sheets to produce integrally stiffened structures with limited fasteners and less weight than…

Joining titanium (Ti) alloys with conventional processes is difficult due to their complex structural properties and ability of phase transformation. Concerning all the difficulties, diffusion bonding is considered as an appropriate process for joining Ti alloys. Ti6Al4V, which is an α+β alloy widely used for aero engine component manufacturing, is diffusion bonded in this investigation. The diffusion bonding process parameters such as bonding temperature, bonding pressure, and holding time were optimized to achieve desired bonding characteristics such as shear strength, bonding strength, bonding ratio, and thickness ratio using response surface methodology (RSM). Empirical relationships were developed for the prediction of the bond characteristics, and sensitivity analysis was performed to determine the increment and decrement tendency of the shear strength with respect to the bonding parameters. Various criteria were applied to achieve the desired bond characteristics and their effects; optimum values and limits were evaluated through graphical and numerical optimization. The predicted and experimented results are validated and found that they are in good agreement with each other. The microstructural examination and X-ray diffraction (XRD) analysis…

This specification covers aluminum-beryllium powders consolidated by hot isostatic pressing (HIP) into the form of blocks, blanks or shapes.

Various research regarding new types of fabrication and modifications of Aluminium alloy to improve the existing properties are going on. The wide range application of aluminium alloy is in aerospace and Automobile Industries. The demand for this material improved by mechanical properties with little to zero increment in weight. The current work is based on the fabrication of hybrid aluminium metal matrix composites with the addition of TiC (Titanium Carbide) and Al2O3 (Aluminium Oxide) reinforcement particle using stir casting technique. Three types of hybrid composite samples were prepared based on the weight percentage 5% Al2O3+0% TiC (sample-1), 8% Al2O3 + 12% TiC (sample-2), 20% Al2O3+15% TiC (sample-3). The objective of the study is to analyze the mechanical and corrosion properties of the hybrid composite with the influence of the reinforcement and varying the weight fraction of the particles. Overall, It is observed that a gradual increase in the hardness value in sample-1(83 BHN), Sample-2 (88 BHN) and sample-3 (96 BHN). This trend can be explained by the particulate strengthening of TiC over the soft ductile…

Friction Stir Process (FSP) was employed for surface modification of steel, titanium, aluminum and magnesium-based alloy has been significantly revised through the last decade. Friction Stir Process can improve surface properties such as hardness, abrasion resistance, ductility, strength, fatigue life, corrosion resistance and formability without upsetting the bulk properties of the material. The aluminum alloy having low ductility and softness characteristics are restricted because of their poor tribological properties. Preliminary studies reveal that, an ideal circumstance is to improve the aluminum alloy material life cycles by the way of strengthening the surface layer which can be modified through reinforcing nanoparticles through FSP. The main objective of the study is to improve the surface properties of AA8011 by adding nanoparticles such as SMA and silicon nitrate (Si3N4) through friction stir process. By the way, this experiment was carried out to obtain three set of samples like virgin AA8011, AA8011 with shape memory alloy and AA8011 along with shape memory alloy and silicon nitride during FSP under optimal process parametric condition. The nanoparticles distribution was improved after…

Inconel 825 is nickel (Ni)-iron (Fe)-chromium (Cr) alloy with additions of copper (Cu), molybdenum (Mo), and titanium (Ti). The alloy has excellent resistance to corrosion and is often the most cost-effective alloy in sulphuric acid piping vessels and chemical process equipment. No attempt of applying MQL with three nanofluids was reported conferring to the works accessed. The present study is focused on evaluating the effect of the addition of three nanoparticles (CuO, Al2O3, and CNT) in vegetable oil applied by MQL mode during turning of Inconel 825 with coated carbide tool. Cutting force, surface roughness, and tool wear are evaluated. The results showed that the addition of nCNT substantially improved the machining performance and smaller flank the tool edge, while the adhesion and abrasion are observed as wear mechanism and better results are obtained at 0.5% of nCNT+ vegetable oil to produce the lowest values.

The surface properties have a vital role in the overall performance of the parts like brake shoe pad and other frame system. The mechanical and residual stress measurements of aluminium alloy 5083 were investigated on friction stir processed plates using the reinforcements of chromium oxide (Cr2O3) and titanium dioxide (TiO2) separately as well as combination of these powders. A comparative study was made to analyze the effects of reinforcements, tool type (cylindrical and threaded), parameters and the volume fraction of the reinforcements. The mechanical properties such as surface hardness and residual stress of the friction stir processed specimens were investigated. The experimental results shows that there was a significant increase in surface hardness (118 HRC) as well as a decrease in residual stress compare to the base metal. This study also reveals that the threaded tool with a reinforcement of Cr2O3 and TiO2 reflected better mechanical properties than the cylindrical tool. The SEM images show that the uniform distribution of reinforcement in the processed zone. The surface-hardened plates can be used in brake shoe pad…