Effect of Stainless Steel Flakes Content on Mechanical Properties and Microstructure of Cast 96.66% Pure Aluminum

Abstract

Stainless steel flakes-reinforced cast aluminum matrix composites were produced using aluminum alloy of 96.66% purity as matrix material and different steel flakes contents as reinforcements. Aluminum matrix specimens with no steel flakes fillers addition were also produced for performance comparison. All specimens were cast into a slightly heated rectangular quenched steel mold, the temperature of which was 35 °C. Both matrix aluminum specimens and aluminum matrix composite specimens underwent tensile and bending tests as well as hardness measurements and microstructural investigation. As observed through microstructural examination, the interdendritic regions do not seem to be affected by steel flakes addition on their at% chemical composition, which remains Al:Fe:Mn:Mg ; 92.28:3.75:2.96:1.01, but only on their size. An increase of the flexure strength of about 20% was achieved by steel flakes-reinforcement of the matrix aluminum. In the case of the highest wt% addition, groups of steel flakes of high directivity towards solidification kernels were observed. These steel flakes group formations resulted in an impressive hardness increase, performing as hard support elements.