Microstructure and mechanical properties of Al-Fe-V-Si aluminum alloy produced by electron beam melting

Abstract

Atomized, pre-alloyed Al-8.5Fe-1.3V-1.7Si (wt%) powder was used to fabricate solid components by electron beam melting (EBM). The residual porosity, chemical composition, microstructure and mechanical properties have been investigated. Results show that the relative density of as-built alloy under the optimized processing parameters was 98.2%. Compare to the initial alloy powder, the EBM parts demonstrated a restricted aluminum loss (~1wt%) and a quite low oxygen pickup. The microstructure of the deposits was non-uniform. The fusion zone and heat affected zone exhibited a large number of fine spherical Al12(Fe,V)3Si particles (30–110nm) distributed uniformly in the α-Al matrix. Some coarser Fe- and V-riched rectangle-like AlmFe phase (m=4.0–4.4) with 100–400nm in size was precipitated in the melting boundary zone. The microhardness of the EBM samples was 153 HV in average. The average ultimate tensile strength (UTS) reached 438MPa with the elongation of 12%. A ductile fracture mode of the tensile specimens was also revealed.