Heterogeneity of microstructure, texture and mechanical properties along the building direction of Ti-6Al-4V alloy developed by SLM

Selective Laser Melting (SLM) is of great interest to the aerospace industry due to its ability for producing components with complex geometries. The laser melting process induces a high cooling rate (10 5-10 7 K/s) and a germination by epitaxy which leads to a columnar microstructure. In the case of Ti-6Al-4V the rate of cooling from the β domain generates a martensitic α' structure made up of fine needles. The present work describes the microstructural, textural and mechanical heterogeneities along the building direction of Ti-6Al-4V samples produced by SLM with two strategies that have different melt pool size. Characterizations show that both strategies lead to a martensitic microstructure but only the SLM with the greater melting area allows to get homogeneous hardness, texture and β grain size (reconstructed by ARPGE) along building direction.