材料科学
韧性
脆性
合金
延展性(地球科学)
钛合金
马氏体
断裂韧性
应变硬化指数
复合材料
变形(气象学)
硬化(计算)
回火
变形机理
位错
冶金
微观结构
蠕动
图层(电子)
作者
Chongle Zhang,Jinyun Zhang,Xiangyun Bao,Jiao Li,D.D. Zhang,Gang Liu,Jun Sun
出处
期刊:Acta Materialia
[Elsevier]
日期:2024-01-01
卷期号:263: 119540-119540
被引量:1
标识
DOI:10.1016/j.actamat.2023.119540
摘要
Precipitates in alloys are traditionally considered as dislocation obstacles that often lead to high stress concentration and even microcracks owing to the strain incompatibility of semi-coherent interfaces, a cause of progressive strain localization and the origin of the strength-toughness conflict in engineering materials, such as titanium (Ti) alloys. Based on the metastability engineering, here we architect hierarchically ordered coherent interfaces for strength-toughness optimization through densely dispersed nanomartensites in a ductile Ti-Cr-Zr-Al alloy with ultrahigh specific-strength and superior fracture toughness. It is unveiled that these ordered coherent interfaces simultaneously serve as dislocation obstacles and sources, leading to a sustainable and self-hardening deformation mechanism via hierarchical nanomartensite-dislocation interactions for ultra-high strength and toughness of Ti alloys. These nanomartensites are thermally stable at elevated temperature less than 400 °C, above which tempering-induced ductile-to-brittle transition occurs due to the decomposition of hierarchically ordered nanomartensites and the spheroidization of prior β lamellae. The design strategy of hierarchically ordered coherent interfaces confers our cost-effective nanomartensite Ti alloys an unprecedented combination of strength, ductility and toughness, which provides a new pathway in the microstructural design for strong and ductile structural materials with superior fracture resistance.
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