Ternary Al–Mo–Y phase diagram and the new phase Al4Mo2Y

Abstract

Abstract The phase equilibria in the Al–Mo–Y system have been experimentally investigated at 873 K. The existence of 10 binary compounds and 1 ternary phase Al43Mo4Y6 has been confirmed by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al4Mo2Y with space group I4/mmm (No. 139) has been found at 873 K. The structure, phase stability, elastic properties and densities of state of the Al4Mo2Y compound have been theoretically investigated by using first-principles calculations. The result of cohesive energy proves that Al4Mo2Y is stable. The elastic constants, bulk modulus, shear modulus, Young's modulus, the ratio of bulk modulus/shear modulus and Poisson's ratio of Al4Mo2Y are presented. According to the phase-disappearing method, the solubility of Al in Mo, AlMo3 and Al8Mo3 phase is determined to be about 16 at.%, 7.5 at.% and 1 at.%, respectively.