The current study aims to investigate the effects of process parameters on mechanical and microstructural characteristics of Al 6061-SiC composite fabricated via squeeze casting. Seventeen experiments in total have been conducted according to Box-Behnken experimental design which contained three process parameters (squeeze pressure, melt temperature, and SiC wt.%) while recording the responses including ultimate tensile strength, hardness, and percentage elongation. ANOVA (analysis of variance) was employed to evaluate the significance and prediction capability of mathematical models developed through regression analysis. The results indicate that squeeze pressure, melt temperature, and SiC wt.% significantly affect the responses whereas ductility is drastically reduced at higher concentrations of SiC reinforcement. SEM micrographs of failed test specimen have been found to be indicative of ductile fracture at higher levels of squeeze pressure and melt temperature. The multi-objective optimization problem has been transformed to an equivalent single-objective problem using grey relation analysis. The desirability analysis revealed optimum setting of process parameters which was confirmed to have improved the ultimate tensile strength by 1.61%, hardness by 1.56%, and percentage elongation by 11.11% as compared to the initial setting.

Multi-response parametric optimization of squeeze casting process for fabricating Al 6061-SiC composite

Experimental analysis and optimization on machining of coated carbon fiber and nanoclay reinforced aluminum hybrid composites

In the present work, free-cutting aluminum alloy AA6026 with 1.1 wt.% bismuth addition was fabricated by different melt preparation methods in order to investigate whether the melt preparation route affects the solidification sequence and thus has an influence on the machinability of the alloy. All experiments were designed to simulate variable industrial conditions: addition of bismuth in an induction melting furnace, addition of bismuth in an electric resistance holding furnace, addition of bismuth together with grain refiner, effect of holding time and melt temperature before casting. Detailed thermodynamic analyses (DSC, Thermo-Calc) and microstructural characterization (SEM-EDS, XRD) have been performed to explain the solidification sequence, microstructure development and especially formation of the intermetallic Mg3Bi2 phase.

https://www.mdpi.com/2073-4352/11/4/424/pdf

Mechanism of the Mg3Bi2 Phase Formation in Pb-Free Aluminum 6xxx Alloy with Bismuth Addition

This paper presents an experimental analysis on microstructure, hardness, density and mechanical properties of aluminum hybrid metal matrix composites manufactured through powder metallurgy. The present article dealt with the composite-I (90 wt % − AA2014 + 5 wt % − Al2O3 + 5 wt% − TiB2), composite-II (85 wt % − AA2014 + 5 wt % − Al2O3 + 10 wt% − TiB2) and composite-III (85 wt % − AA2014 + 10 wt % − Al2O3 + 5 wt % − TiB2) were developed from the elemental powders mixing, die compaction and sintering. Three composites were compacted at a pressure of 350 ± 10 MPa and sintered at 610 ± 10 °C for 2 h in a vacuum hot press under the nitrogen atmosphere. Three composites were measured for microstructural observation, density analysis, porosity, hardness and mechanical properties investigation. In this experimental investigation, particles of alumina and titanium diboride were homogeneously diffused in the aluminum alloy 2014. Composite-I exhibits the 1.4% of average porosity of the composition and 98.5% of it theoretical density. Addition of reinforced particles of 15 wt % in the composites has increased hardness, porosity and reduced the sintered density.

Microstructure and Mechanical Properties of Alumina and Titanium Diboride Containing AA2014 Hybrid Composites

Based on requirements of automotive applications for weight reduction, aluminum alloys become more popular as lightweight material. 5754 aluminum alloys are commonly preferred in automotive industry due to high strength and good formability. 5754 sheet materials produced by either direct chill casting (DC Casting) or twin roll casting method (TRC) by aluminum sheet manufacturers. In present study, 5754 aluminum alloys were both casted by DC Casting and TRC methods. On the purpose of good deep drawing behavior and high strength for automotive components, alternative thermo-mechanical processes were carried out in laboratory scale. Metallographic examinations were done in order to investigate influence of diversified casting methods on grain structure. Besides that, tensile test and deep drawing test were conducted for characterization of specimens. SEM-EDS and SEM-EBSD analyses were fulfilled to examine the structure of intermetallic on material and texture development.

Comparison of Diversified Casting Methods on Mechanical and Microstructural Properties of 5754 Aluminum Alloy for Automotive Applications

Pb-based alloys such as AA6262, AA2011 and more recently AA6026 are used as free-machining aluminum alloys for automotive and electronic applications However, in order to comply with Automotive End of Life Vehicles (ELV) and Restriction of Hazardous Substances (RoHS) directives, Pb-based alloys slowly need to be phased out A Pb-free machining grade 6xxx aluminum alloy based on Sn was developed and its machinability evaluated Microstructure analysis of the Al–Mg–Si–Sn–Cu alloy revealed the presence of (98 wt%) Sn–Mg2Sn eutectic phases, which have a low melting point of ~203 °C, and are responsible for providing good machinability Homogenized billets of the alloy were extruded and heat treated to T6 temper Yield strength and ultimate tensile strength of the Pb-free alloy were comparable to those of the conventionally used Pb-based AA6262-T6 alloy Machinability studies of the alloy were conducted by evaluating the effect of cutting speed, feed rate and depth of cut on surface roughness, chip size and form of chip produced during the turning operation The machinability of the Sn containing alloy was found to be superior to that of non-machining grade 6xxx alloys AA6061-T6 and AA6082-T6 and comparable to that of Pb-based free-machining alloy AA6262-T6

Investigations on Pb-Free 6000 Series Aluminum Alloy for Machining Applications

High costs, consistency and scalability are the major challenges in development of metal matrix composites. To overcome these challenges, a novel process has been demonstrated in which pneumatic powder injection was used instead of the conventional mechanical stirring process. In this study, aluminum–titanium carbide particulate composites were prepared in situ by injection of mixed salt of titanium (K2TiF6-potasium titanium fluoride salt) and graphite powder through submerged lance into molten aluminum. Uniform distribution of equiaxed Al3Ti (aluminum–titanium intermetallic) particles and TiC (titanium carbide) particles were achieved depending on the reaction temperature and holding time. SEM-EDS confirmed the presence of submicron TiC particles distributed throughout the matrix. TiC particles generated in situ are thermodynamically more stable and tend to have cleaner matrix particle interfaces. More than 15% improvement in elastic modulus along with significant improvement in other mechanical properties was achieved by up to 10 wt% TiC reinforcement.

Development and Characterization of In-situ Aluminum–Titanium Carbide Composites Prepared by Pneumatic Powder Injection Route

An investigative study was carried out to understand the effect of homogenization, hot and cold rolling as well as annealing cycle on improvement of deep drawing and anodizing quality of thin AA3003-O sheets Poor drawability of the sheets was attributed to a coarse average grain size, high cube texture intensity and low average normal anisotropy (\( \overline{R} \)) Amount of Al–TiB grain refiner was increased in the casting stage, leading to a significant reduction in as-cast grain size The 2-stage homogenization cycle was optimized to maximize the conversion of β-phase (Al6(Mn,Fe)) to α-phase (Al(Mn,Fe)Si), their number density, the area fractions of the precipitates and the electrical conductivity The degree of hot rolling was increased to reduce the cube texture intensity in annealed circles The annealing cycle was optimized to obtain the best combination of grain size, mechanical properties (UTS and total elongation), \( \overline{R} \) and average planar anisotropy, ΔR AA3003-O circles successfully passed the deep drawing test without any tearing or deformation, up to a draw ratio of 2 Also the presence of the α-phase led to an improvement in the anodizing quality of the final product

Anirban Giri

Papers

Investigations on Pb-Free 6000 Series Aluminum Alloy for Machining Applications

Development and Characterization of In-situ Aluminum–Titanium Carbide Composites Prepared by Pneumatic Powder Injection Route

Deep Drawing and Anodizing Quality Improvement in AA3003-O Alloy by Optimization of Homogenization, Rolling and Annealing