Microstructural evolution and EBSD analysis of AlSi10Mg alloy fabricated by selective laser remelting

Abstract

This study characterizes microstructural evolution and texture orientation of AlSi10Mg components through selective laser melting (SLM) by adopting different strategies during remelting. SLM selectively melts the powders and solidified layer, generating a moving melt pool and resulting in unique microstructure. The microstructural evolution, grain sizes and the texture orientation of the fabricated samples were investigated using different scanning strategies by optical microscopy, scanning electron microscopy, and electron back-scattered diffraction. Experimental results show that the inter-connected net shape of the AlSi eutectic structure tends to be widen as a result of the increase of the Si precipitation phase. The grain sizes become smaller and produce more subgrains effected by high thermal conductivity of the solidified layer. The average hardness and Young's modulus increased to 2.32 GPa and 93.26 GPa, respectively. When the remelting scanning direction is rotated to 90°, the cellular microstructure comes into domination. Due to the remelting processing, the preferential grain growth orientation is 〈100〉 both along the scanning and building direction, and the crystallographic texture is enhanced. Results show distinct epitaxial growth along the heat flow with <100> orientation can be obtained and hence isotropy is strengthened.