First-principles study on the ideal strengths of typical hcp metals

The ideal strengths of several hcp metals (Be, Mg, Ti, Zn, Y, Zr and Ru) have been investigated by first-principles stress strain calculations. The results reveal that the ideal shear strengths of these hcp metals occur mainly on basal plane {0001} or prismatic plane < 10 (1) over bar0 >. Particularly, for basal plane the peak shear stress in < 10<(1)over bar>0 > direction is smaller than that in < 11<(2)over bar>0 > direction. The calculated tensile strengths and elongations in < 0001 > direction are broadly consistent with the available theoretical results. Furthermore, both the ideal shear and tension strengths become stronger with the decreasing of c/a for these simple metals or transition metals. The calculated electronic structure further reveals the inherent mechanism of hcp metals.