TY - JOUR
T1 - The direct and indirect effects of nanotwin volume fraction on the strength and ductility of coarse-grained metals
AU - Guo, X.
AU - Ouyang, Q. D.
AU - Weng, G. J.
AU - Zhu, L. L.
N1 - Funding Information:
We wish to thank an anonymous reviewer for his/her helpful comments. X. Guo acknowledges the support from National Natural Science Foundation of China (Project nos. 11372214 and 11102128 ) and Elite Scholar Program of Tianjin University . G.J. Weng thanks the support of NSF Mechanics of Materials and Structures Program under CMMI-1162431 . L.L. Zhu acknowledges the support from National Natural Science Foundation of China (Project nos. 11302189 and 11472243 ).
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/3/7
Y1 - 2016/3/7
N2 - Coarse-grained (CG) metals strengthened by nanotwinned (NT) regions have an excellent combination of high strength and good ductility. In this paper, numerical simulations based on the mechanism-based strain gradient plasticity and the Johnson-Cook failure criterion are carried out to investigate the direct and indirect effects of volume fraction of the NT regions and several other key attributes on the strength and ductility of the CG metal strengthened by NT regions. Our results indicate that twin spacing, shape, distribution, and volume fraction of NT regions all have significant effects, and that, as the volume fraction increases, the roles played by the twin spacing and shape of NT regions also change. At low volume fraction of NT regions, their shape is found to have a significant influence on the overall ductility. As the volume fraction increases, the shape effect on the ductility is found to diminish even though the effect on the strength is noted to continue to enhance. While twin spacing and volume fraction of NT regions have shown different effects on the ductility, the effect of twin spacing always decreases as the volume fraction increases. During the simulations we have also discovered several intrinsic deformation and failure mechanisms through the analysis of microcrack initiation sites and microcrack propagation paths. It is believed that this simulation has revealed significant insights into the roles of volume fraction, twin spacing, shape, and distribution of NT regions on the strength and ductility of this novel class of materials.
AB - Coarse-grained (CG) metals strengthened by nanotwinned (NT) regions have an excellent combination of high strength and good ductility. In this paper, numerical simulations based on the mechanism-based strain gradient plasticity and the Johnson-Cook failure criterion are carried out to investigate the direct and indirect effects of volume fraction of the NT regions and several other key attributes on the strength and ductility of the CG metal strengthened by NT regions. Our results indicate that twin spacing, shape, distribution, and volume fraction of NT regions all have significant effects, and that, as the volume fraction increases, the roles played by the twin spacing and shape of NT regions also change. At low volume fraction of NT regions, their shape is found to have a significant influence on the overall ductility. As the volume fraction increases, the shape effect on the ductility is found to diminish even though the effect on the strength is noted to continue to enhance. While twin spacing and volume fraction of NT regions have shown different effects on the ductility, the effect of twin spacing always decreases as the volume fraction increases. During the simulations we have also discovered several intrinsic deformation and failure mechanisms through the analysis of microcrack initiation sites and microcrack propagation paths. It is believed that this simulation has revealed significant insights into the roles of volume fraction, twin spacing, shape, and distribution of NT regions on the strength and ductility of this novel class of materials.
KW - Johnson-Cook failure criterion
KW - Microstructure
KW - Nanotwin
KW - Strain gradient plasticity
KW - Twin spacing
KW - Volume fraction
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U2 - 10.1016/j.msea.2016.01.090
DO - 10.1016/j.msea.2016.01.090
M3 - Article
AN - SCOPUS:84961294881
SN - 0921-5093
VL - 657
SP - 234
EP - 243
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
ER -