Heterostructured titanium composites with superior strength-ductility synergy via controllable bimodal grains and <c+a> dislocation activity
Jiajing Chen, Yuanfei Han, Zichao Wei, Shaopeng Li, Zhonggang Sun, Liang Zhang, Guangfa Huang, Jianwen Le, Di Zhang, Weijie Lü
Abstract
Constructing heterostructures in particulate reinforced titanium matrix composites (PRTMCs) to evade the strength-ductility trade-off dilemma is much more difficult than in metals. Here, we proposed a novel and controllable strategy of simple powder assembly to fabricate bimodal-grained PRTMCs, this customized strategy makes coarse grains (CGs) surrounded by ultrafine-grained (UFG) matrices, conferring a superior strength-ductility combination not achievable by their traditional homogeneous counterparts. We found that such heterostructures appear to promote storage of mostly<c+a> dislocations in CGs and accumulation near the CG/UFG boundaries. Moreover, hybrid reinforcements also activate multiple hardening mechanisms, inducing high ductility.