Processing and characterization of Al-Si-Mg alloy made through 3D printing and comparison with equivalent cast alloy

Abstract

Additive Manufacturing (AM) or 3D printing has attracted the attention of industries due to faster process for intricate shaped components. However, accuracy and reliability are the important requirements of aerospace components. Selective laser melting(SLM), also referred to as laser powder bed fusion (L-PBF) is an AM technique developed to melt and fuse metallic powders via a high power-density laser. An example of a complex shaped component, impeller made up of Al alloy is studied through SLM as well as through conventional casting method. Through SLM process, precipitation-hardenable AlSi10Mg alloy (equivalent to cast alloy AЛ4 of GOST 1583–93) is processed. Microstructural and mechanical tests were carried out and compared with equivalent cast alloy AЛ4. Ultimate Tensile Strength (UTS), Yield Strength (YS) and Elongation (%El) of 3D printed samples are 26 %, 45 % and 68 % higher than cast alloy in X direction respectively while UTS, YS and %El of 3D printed samples are 30 %, 32 % and 20 % higher than cast alloy in Z direction respectively. Improvement in mechanical properties is attributed to fine grained microstructure of 3D printed alloy. Hardness of 3D printed samples is 35 % higher than the cast alloy. It is observed that component manufactured through SLM has better surface finish as compared to cast component and meets the specification requirements of impeller.