Microstructures and mechanical property of AlMgScZrMn - A comparison between selective laser melting, spark plasma sintering and cast

Abstract

Whether selective laser melting (SLM) printed AlMgScZrMn alloy possesses more excellent performances than other processing routes was unknown. In the study, the microstructures and mechanical properties of AlMgScZrMn alloys fabricated by selective laser melting (SLM), spark plasma sintering (SPS) and cast were comparatively investigated. SLM printed sample shows columnar and equiaxed duplex grains with average grain size about 7 μm, which is coarser than SPS consolidated sample with finest equiaxed grain (4 μm) but smaller than casting sample with coarse equiaxed grain (25 μm). SLM printed sample shows the highest tensile strength (394 ± 5 MPa) and elongation (10.5 ± 1.2%) than SPS sample (231 ± 3 MPa, 0.59 ± 0.21%) and cast sample (188 ± 2.3 MPa, 3.7 ± 0.58%), although SPS sample has the finest equiaxed grains. For SPS sample, previous particle boundary (PPB) with oxide inclusion significantly deteriorates ductility. For cast sample, the coarse equiaxed grain with intergranular eutectic leads to inferior strength. In addition, the average dimension of Al3(Sc,Zr) particle in SLM sample is about 1–10 nm, which is much finer than SPS sample (0.5–0.8 μm) and cast sample (1–2 μm). The present study will provide a basis for the future industrial applications of the AlMgScZrMn alloy.