Material hardness, one of the most obvious physical properties, has always been a research focus. Being the highest hardness material,in nature, diamond becomes the benchmark in research field of material hardness.
The team, led by Professor Sun Hong, from Shanghai Jiao Tong University(SJTU) has been dedicated to studying the material hardness through first-principles calculations. According to the experiments, the diamond indenter with lower hardness did not break when it cut or was pressed against the nt-Dia with higher hardness. Based on this observation, the team put forward the Maximum-stress Indentation model by which the team conducted the deformation simulation of nt-Dia and successfully explained the experimental fact that the hardness of nt-Dia could reach 200GPa at abnormal Hall-Petch zone.
The result was recently published on the Physical Review Letter 117, 116103 (2016). The research was supported by the National Nature Science Foundation（11574197） and Ministry of Science and Technology of China（2016YFA0300500）.
Translated by Zheng Mengyan Reviewed by Lu Siyu