|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Additive Manufacturing: Building the Pathway towards Process and Material Qualification
||Investigating Stress Relaxation Behavior and Mechanisms in Ti- and Ni-alloys by In Situ Neutron Diffraction: Application to Additive Manufacturing
||Zhuqing Wang, Alexandru D. Stoica, Dong Ma, Allison M. Beese
|On-Site Speaker (Planned)
The complex thermal histories in additive manufacturing result in the buildup of residual stresses, whose amount depends on the stress relaxation behavior of the deposited material and substrate. We investigated stress relaxation behavior and mechanisms in conventionally processed and additively manufactured Ti-6Al-4V and Inconel 625 (IN625) through high temperature compression tests with in situ neutron diffraction. Neither stress partitioning nor phase transformation was present in Ti-6Al-4V; rather stress relaxation was primarily controlled by dislocation glide and climb in both materials. Stress relaxation occurred more slowly and stabilized to a higher level in IN625 compared to Ti-6Al-4V, as solute atoms and secondary phases dispersed in the gamma matrix in IN625, but not in the alpha laths in Ti-6Al-4V, impede dislocation motion. A rheological model will be presented to describe the relaxation behavior of each material, which can be used in thermomechanical models for AM to predict and mitigate residual stresses.
||Planned: Supplemental Proceedings volume