Effect of building orientation and heat treatment on the anisotropic tensile properties of AlSi10Mg fabricated by selective laser melting

Abstract

In this paper, we investigated the effects of building orientation and heat treatment temperature on the anisotropy of SLM-formed AlSi10Mg specimens. Three different deposition orientations of 0°, 45° and 90° and heat treatment temperatures of 270 °C, 300 °C and 330 °C were used to hold the specimens for 2 h, followed by furnace cooling. The metallographic organization, fracture morphology, grain size and morphology, grain orientation and distribution were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). SEM metallographic shows that the white cell structure is eutectic Si where Si grid-like structure distributes around α-Al dendrites. EBSD results show that all specimens consist of a large number of grains growing along< 001 > direction, which is the preferred orientation. The organizational changes in grain size, distribution and low-angle grain boundaries (LAGBS) caused by orientation and heat treatment were analyzed to confirm the anisotropy of the SLMed AlSi10Mg alloy and to analyze and explain the reasons for the poor plasticity of the 90° orientation. The present results provide new insights into the effects of deposition direction and heat treatment parameters on the microstructure and properties of AlSi10Mg alloy prepared by SLM.