Improving Dynamic Mechanical Properties and Inhibiting Adiabatic Shear Bands of the Molybdenum Single Crystal by Adding Nb Element

The adiabatic shear band is a common dynamic failure mechanism in metal materials at high strain rates. In this work, a new approach was proposed to improve mechanical properties and inhibit the formation and propagation of the adiabatic shear band in the pure Mo single crystal. The microstructure evolution of the pure Mo and Mo-Nb single crystals subjected to the dynamic load was investigated by EBSD and TEM. At a strain rate of 2500 s-1, the developed adiabatic shear band was totally distributed in the pure Mo single crystal, and the slip is the main deformation mechanism. A thinner adiabatic shear band was distributed in the Mo-3Nb single crystal accompanied by a few bands of deformation twins and then disappeared in the Mo-6Nb single crystal, replaced by the {112}<111> deformation twinning. At high strain rates, the dynamic deformation mechanism of the Mo single crystal is sensitive to the Nb element, which attributes to the reduction of the generalized stacking fault energy.