|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||L-58: Interface Controlled Work Hardening Ability in Ultrafine-grained Ti-6Al-4V Alloy with Bimodal Microstructure
||Yan Chong, Tilak Bhattacharjee, Ruixiao Zheng, Tsuji Nobuhiro
|On-Site Speaker (Planned)
In metallic materials the increase of yield strength with grain refinement is usually accompanied by the loss of uniform elongation, which is a so-called trade-off relationship of strength and ductility. Such a relationship was also found in the titanium alloy Ti-6Al-4V with equiaxed microstructures, in which the uniform elongation of ultrafine-grained (UFG) equiaxed microstructures (d≤1μm) decreased to only ~1%. However, the uniform elongation can be restored to 5~8% simply by transforming the UFG equiaxed microstructure into UFG bimodal microstructure via annealing in the two phase region followed by water quenching. In-situ tensile deformation in TEM indicated that the improved uniform elongation in the UFG bimodal microstructure was attributed to the introduction of interfaces between equiaxed α grain (αp) and transformed β area (βtrans). In the early stage of deformation, dislocations were emitted from the αp/βtrans interface in the bimodal microstructure while formed inside the α grains in the equiaxed microstructure.