Toughening and maintaining strength of diamond with substitutional doping boron and nitrogen

As the hardest materials, natural and synthetic diamonds have been widely used in industrial production, but the inherent brittleness may strongly restrict their applications. In this work, aiming at the enhancement of the ductility of diamond, the effects of substitutional doping boron (B) or nitrogen (N) on the mechanical properties of diamond were systematically investigated using first-principles calculations. It was found that doping B or N could substantially induce partial slip that leads to atomic reconfiguration at the defect region of diamond, which results in an increase of ductility while retains the high strength of diamond. The results may help us to gain an insight into the enhancement of the mechanical properties of the material by doping substitutional impurities at atomic scale.