Toward strength-ductility synergy in trimodal grain structured metal composites by actively tuning coarse domains
Zhanqiu Tan, Xiaowen Fu, Quan Zheng, Renbang Lin, Mingliang Chen, Genlian Fan, Ding‐Bang Xiong, Zhiqiang Li
Abstract
Trimodal grain structure was effective to balance the strength-ductility trade-off in ultrafine-grained metals, but the relationship between microstructures and mechanical performance is unclear. Here the dimension of coarse grain (CG) domains was elaborately tuned in the trimodal CNT/2024Al composites, and an excellent strength-ductility combination (Tensile strength: 716 ± 5 MPa, Elongation: 9.1 ± 0.3%) was achieved by optimizing the CG bands (∼4.4 µm in width). We found that the size of CG bands hardly affected strain hardening rate, but caused different crack-blunting behaviors, which was responsible for the superior strength-ductility synergy. This work highlights the importance of CG domains design in heterostructured materials.Trimodal grain structured CNT/2024Al composites with different coarse-grained (CG) bands