Modeling and investigation for atomic diffusion and mechanical properties of TiAl/Ti3Al interface: temperature effect

Abstract

The effect of temperature on the diffusivity and mechanical property of the TiAl/Ti3Al interface at nanoscale was investigated using molecular dynamics (MD). The diffusion mechanism is atomic self-diffusion in the TiAl or Ti3Al blocks at the temperatures of 673 ~ 1273 K. However, self-diffusion and asymmetric counter-diffusion determine the diffusion process. The self-diffusion of atoms in the Ti3Al block is much better than that in the TiAl block under the same temperature. The average atomic diffusive distance in the TiAl block is significantly farther than that in the Ti3Al block owing to its lower melting point and greater numbers of slipping system. The yield strength of the joint after diffusion welding at the temperatures of 673 ~ 1373 K is about 1.2 GPa higher than that at 1473 K. The temperature has little effect on the mechanical properties of elastic modulus, yield strength, yield strain and flow stress of the diffusion joint at the temperatures of 673 ~ 1273 K. However, the elastic modulus, yield strength and flow stress decrease gradually with the increase in temperature at 1273 ~ 1473 K.