On mechanical stability of molybdenum

Investigations of the strength properties of materials under different loading conditions are of practical importance in many engineering applications. The knowledge of elastic moduli as a function of strain is required for determination of strength properties. In the present work, we have determined the elastic moduli of molybdenum through first principles study of the energy changes under three different loading conditions namely 'uni-axial tensile deformation' along [ 001] direction, 'uni-axial tensile loading' along [ 001] direction and 'hydrostatic tensile loading'. The stability conditions for the system are expressed in terms of the elastic moduli and analyzed along the deformation paths corresponding to these three loading modes. The theoretical spall strength (sigma(S)), tensile strength (sigma(T)) along [ 001] direction and hydrostatic tensile strength ( sigma(H)), are evaluated as a stress at the first onset of the instability for three loading conditions, respectively. The calculated equilibrium volume and elastic moduli are compared with that reported from experimental and other theoretical works.