Ductile Ti-rich high-entropy alloy controlled by stress induced martensitic transformation and mechanical twinning

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:763

Article

Wang, Lu¹  Fu, Chao¹  Wu, Yidong¹  Li, Runguang¹  Wang, Yandong¹  Hui, Xidong¹ 

[1] Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China

关键词: High-entropy alloys;    Ductility;    Stress-induced martensitic transformation;    Martensite variants reorientation;    Mechanical twinning;   

DOI  :  10.1016/j.msea.2019.138147

来源: Elsevier

【 摘 要 】

Body centered cubic type of refractory high-entropy alloys (HEAs) have high strength at room and elevated temperatures, but suffer from the strength-ductility trade-off dilemma, making their application for structural materials severely impeded. In this article, we report a strategy to break this puzzle by introducing successive stress-induced martensitic transformation (SIMT) and mechanical twinning in Ti-rich refractory TiZrHfAlNb HEA via controlling the grain size. The HEA exhibits superior ductility featured by fracture and uniform elongation as high as 40% and 33%, respectively, at ambient temperature. The plasticizing and toughening mechanisms for the HEA with different grain sizes can be described as following: in the HEA with small grains, the SIMT takes place followed by the martensite variants reorientation; in that with coarse grains, mechanical twinning of alpha '' phase comes up with the preferential orientation relationship of [111]beta//[101]alpha ''(M)//[-10-1]alpha ''(T) after the SIMT.

【 授权许可】

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