Synchronous improvement of strength and ductility is a challenging and longstanding problem in the further development and engineering applications of titanium matrix composites (TMCs). In this study, we designed a novel heterogeneously optimized TMC for the first time, which features fine grain/coarse grain (FG/CG) regions embedding in-situ interfacial submicron-TiB/micron-TiC and intragranular nano-TiB whiskers. The TMCs achieved a strength-ductility combination, representing a nearly 30% increase without any reduction in ductility compared with the matrix alloy. The bimodal structures of the TMCs, as well as the micro-nano reinforcements and their interfacial/intragranular distribution, play a predominant role on the strengthening-toughening effect. Besides, the various dislocation behaviors including multiple slips, slip transmission across grain boundaries and activation of more 〈c + a〉 dislocations near the reinforcements, contribute to the desirable ductility. These findings highlight the untapped potential for improving mechanical properties of metal matrix composites.

强度和延展性的同步提高是钛材料进一步开发和工程应用中长期存在的难题基体复合材料（TMC）。在这项研究中，我们首次设计了一种新型的异质优化TMC，其特征是细晶/粗晶（FG/CG）区域嵌入原位界面亚微米TiB/微米TiC和晶内纳米TiB晶须。TMC 实现了强度-延展性组合，与基体合金相比，延展性提高了近 30%，而延展性没有任何降低。TMCs的双峰结构以及微纳米增强体及其界面/晶内分布对强韧化效果起主导作用。此外，各种位错行为包括多次滑移、跨晶界的滑移传输和更多〈c  +  a〉的激活增强材料附近的位错有助于获得理想的延展性。这些发现凸显了改善金属基复合材料机械性能的尚未开发的潜力。