Mechanism of solute hardening and dislocation debris-mediated ductilization in Nb-Si alloy

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外文摘要：Niobium(Nb)is sensitive to even minute quantities of silicon(Si)solutes,which are known to induce pronounced hardening.However,the underlying mechanism for hardening remains elusive since the ef-fect of Si solutes on dislocation behavior is unclear.Here,using tensile testing,in-situ microscopy and nanomechanical testing,the behavior of dislocations in dilute Nb-Si alloys,containing from 0 at.％to 0.8 at.％Si,is investigated.We show that the hardness,strength and strain hardening rate increase from two to four times,while the uniform elongation in tension only reduces 50％as the Si content increases.Dislocations evolve from complex entangled patterns in Nb to parallel long-straight screw dislocation-dominated structures in Nb-Si alloys.In-situ indentation reveals that the origins of the marked harden-ing in Nb-Si alloy are the reduction of dislocation mobility and cross-slip propensity.Large densities of dislocation debris-superjogs and loops introduced throughout the sample during warm rolling and an-nealing are found to provide active internal dislocation sources,which explain the minimal ductility loss seen in these Nb-Si alloys.These findings can help guide the alloy design of high-performance refractory materials for extreme temperature applications.

外文关键词：

NiobiumSi soluteHardeningDuctilizationDislocation

作者：

Bo-Qing Li、Irene J.Beyerlein、Shuhei Shinzato、Shigenobu Ogata、Wei-Zhong Han

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作者单位：

Center for Advancing Materials Performance from the Nanoscale,State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China

Materials Department,University of California,Santa Barbara,CA 93106-5070,USA

Department of Mechanical Engineering,University of California,Santa Barbara,CA 93106-5070,USA

Department of Mechanical Science and Bioengineering,Osaka University,Osaka 560-8531,Japan

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出版年：

2024

DOI：

10.1016/j.jmst.2024.03.052

材料科学技术(英文版)

中国金属学会中国材料研究学会中国科学院金属研究所

材料科学技术(英文版)

CSTPCD

影响因子：0.657

ISSN：1005-0302

年,卷(期)：2024.203(36)