Effects of alloying elements on the generalized stacking fault energy of Ti5Si3: A first principle study

Influences of six alloying elements on the generalized-stacking-fault (GSF) energy in Ti5Si3 (Ti60Si36) were investigated by the first-principle methods. The GSF energy curve of Ti5Si3 (Ti60Si36) is plotted in the basal{0001}<112¯0>, prism{11¯00}[0001] and pyramidal {21¯1¯2}1/3<21¯1¯3¯>slip system after alloying with six alloying elements. According to the calculation results, the addition of alloying elements will result in a significant decrease of GSF energy, which can promote the generation of prismatic stacking defects and enhance the plasticity of Ti5Si3. In the basal {0001}<112¯0>, prism{11¯00}[0001] and pyramidal {21¯1¯2}1/3<21¯1¯3¯>slip systems, the γus of the possible slip locations decreases gradually with increasing difference in atomic size between Ti and alloying elements. At the same time, through the calculation of elastic constant, it is analyzed that the plasticity of Ti5Si3 will raise first and then fall after the addition of Al atoms with different contents. The addition of alloying elements will decrease the GSF energy, which is caused by the weakening of Ti‒Si bonds. This work may have guiding significance for the alloying design of Ti5Si3 intermetallic compounds.