First-principles study of the mechanical properties of ScAl microalloyed by 4d-transition metals

The structural and elastic properties of B2 ScAl doped with Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd elements are studied by using first-principles calculations. The calculated elastic coefficients of pure ScAl are consistent with other theoretical results. The results of elastic constants indicate that all the ScAl-based alloys discussed are mechanically stable. The bulk modulus B, shear modulus G, Young's modulus Y, Pugh ratio B/G and Cauchy pressure (C-12-C-44) are investigated. It is found that the addition of Ru that prefers Al site in ScAl can increase the stiffness of ScAl and improve its ductility.