The mechanical properties of TCP phase of rapidly cooled molybdenum

Abstract

The rapidly-cooling of pure molybdenum (Mo) at 1010 Ks−1 and the uniaxial tensile of the solid at a strain rate of 2 × 10 s−1 were studied by molecular dynamics simulation; then the structure evolution was investigated in terms of pair distribution function and the largest standard cluster analysis. It is found that Mo melt was cooled into a complex crystal with multiple characteristic lengths. Further analysis revealed that it is a mixture topological close packing (TCP) crystal composed of the dominated A15 phase (Mo-A15) and the less Z phase, with H phase as twin grain boundary. The Phonon spectrum, potential energy, and cohesion energy revealed that Mo-A15 is stable slightly inferior to Mo-bcc. Compared to the prevailing bcc Mo, Mo-A15 holds much higher Young’s modulus, ultimate tensile strength, and Yield strength, being a representative material for barrier layer with high hardness.

Keywords

• LaSCA
• Molecular dynamics simulation
• Topologically close-packing structure
• A15 phase