Neutron diffraction analysis of microstructural evolution and mechanical behavior in an additively manufactured multiphase alloy

Abstract

Additive manufacturing (AM) involves an unprecedented thermal history during solidification and post-melt high-temperature exposure, leading to unique microstructural evolution. In this study, we employed neutron-diffraction-based microstructural analysis to better understand the microstructural evolution and mechanical behavior of AM alloys, with a particular focus on multiphase alloys. Samples of Ti−6Al−4V alloy used as a model material were prepared using electron beam powder bed fusion (EB-PBF) under varying building conditions. Time-of-flight neutron diffraction (TOF-ND) measurements were performed using an iMATERIA (BL20), J-PARC, Japan. Using Rietveld texture analysis (RTA), we revealed the textural evolution during hierarchical microstructural development from solidification to solid-state phase transformations in the EB-PBF process. The effects of building conditions on the textures in the as-built states and their evolution during subsequent tensile loading were analyzed.