Dense dispersed shear bands in gradient-structured Ni

By Yanfei Wang, Chong-xiang Huang, Yusheng Li, F. Guo, Q. He, Mingsai Wang, Xiaolei Wu, R. Scattergood, Yuntian Zhu. International journal of plasticity, 2020

141 citations recorded by the source corpus.

Abstract During tensile deformation, nanostructured (NS) metals often fail soon after yielding by forming a localized shear band. Here we report the observation of high density of shear bands that are homogeneously dispersed in the NS layer of a gradient Ni sample. These shear bands were nucleated at early elastic/plastic strain stage, reached number saturation at ∼3% strain, and remained arrested by the central coarse-grained (CG) matrix during the entire plastic deformation, resulting in a uniform tensile plasticity comparable to that of CG matrix. The formation of dispersed shear bands was promoted by the elastic/plastic interaction between NS surface layer and CG matrix, and affected by the surface roughness and the hardness variation in the NS surface layer. The width of shear bands remained constant, but the intensity of strain accumulation increased almost linearly with applied tensile strain, suggesting a stable shear banding process. Microstructure examination revealed that the strain in shear bands was accommodated by mechanically driven grain boundary migration and grain coarsening. These results clarify the fundamental questions: why/how does the NS layer supported by CG matrix achieve large uniform elongation? Moreover, the findings demonstrate the possibility of activating dispersed stable shear bands by synthesizing gradient architecture for optimized mechanical performances, i.e., a new strategy for evading the strength-ductility tradeoff in NS metals.

Subfields: Materials Chemistry, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/6fabf6f881e94ed5ceb26279de18cd2c5a948482

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Materials Chemistry

1. Yuntian Zhu
2. Yonghao Zhao
3. Yang Cao
4. Hao Zhou
5. Y. Liu
6. Yanfang Liu
7. J. Wang
8. Z. You

In Mechanics of Materials

1. Yuntian Zhu
2. Yonghao Zhao
3. Yang Cao
4. Hao Zhou
5. R. Valiev
6. Xiaolei Wu
7. Terence G. Langdon
8. Xiaozhou Liao

Citations in the corpus

• Critical microstructures and defects in heterostructured materials and their effects on mechanical properties (2020, background): “Besides, the shear bands observed so far in HS materials are bands of strain concentration rather than actual structural shear bands [22,43,50, 51].”