Temperature-dependent hardness of diamond-structured covalent materials
Abstract
Understanding temperature-dependent hardness of covalent materials is not only of fundamental scientific interest, but also of crucial importance for technical applications. In this work, a temperature-dependent hardness formula for diamond-structured covalent materials is constructed on the basis of the dislocation theory. Our results show that, at low temperature, the Vickers hardness is mainly controlled by Poisson's ratio and shear modulus with the latter playing a dominant role. With increasing temperature, the plastic deformation mechanism undergoes a transition from shuffle-set dislocation control to glide-set dislocation control, leading to a steeper drop of hardness at high temperature. In addition, an intrinsic parameter, a3G, is revealed for diamond-structured covalent materials, which measures the resistance to soften at high temperature. Our hardness model shows remarkable agreement with experimental data. Current work not only sheds lights on the physical origin of hardness, but also provides a direct principle for superhard materials design.
Cite
@article{arxiv.1909.11032,
title = {Temperature-dependent hardness of diamond-structured covalent materials},
author = {Xing Feng and Jianwei Xiao and Bin Wen and Jijun Zhao and Bo Xu and Yanbin Wang and Yongjun Tian},
journal= {arXiv preprint arXiv:1909.11032},
year = {2020}
}
Comments
Main manuscript (abstract, 147 words; main text, 2012 words; 31 references; 4 figures and 2 tables, etc.), supplementary materials (4 figures)