The effect of laser scanning strategies on texture, mechanical properties, and site-specific grain orientation in selective laser melted 316L SS

Abstract

Selective laser melting has been used to demonstrate the striking effect of laser scanning strategies on the crystalline texture in 316L SS. The aligned crystal orientation along the tensile direction (Z-axis) could be varied using the scanning strategy. A strong 〈100〉 single crystalline-like texture is obtained in the direction of the laser scan and a 〈110〉 texture was observed in the build direction when using a bidirectional scan without rotation. Fiber texture was observed along the tensile direction when the bi-directional laser scanning vectors were rotated by 67° (Rot-scan) for each layer. The study highlights a correlation between laser scanning strategies with resulting textures, microstructure, and mechanical properties in as-printed bulk 316L SS. The hardness, Young's modulus, and ultimate tensile strength were significantly influenced by the final microstructure, crystallographic texture, and porosity. Furthermore, the applied laser scanning strategies made it possible to tailor crystallographic textures locally within the component. This was demonstrated by printing characters with a fiber texture, in a matrix with ⟨100⟩ texture parallel to the Z-axis.

Keywords

• Selective laser melting
• Texture
• Austenitic stainless steel
• Solidification microstructures