Changes of alloying elements on elasticity and solid solution strengthening of α-Ti alloys: a comprehensive high-throughput first-principles calculations

Herein, the effects of 33 alloying elements on the elastic properties and solid solution strengthening (SSS) of alpha-Ti alloys were systematically studied via first-principles calculations based on a dilute solid solution. All alloying elements in these calculations were thermodynamically favorable, which indicated that these elements could be dissolved in alpha-Ti alloys. Ti35Os had the highest elastic modulus as compared to those of other dilute Ti-based solid solutions. Au, Co, and Pt were found to be promising candidates for improving the ductilities of alpha-Ti solid solution alloys. Solid solution strengthening was analyzed using Cottrell's and Labush's models. Based on the solid solubility, Ir, Rh, Ni, and Pt were found to possess the best solid solution hardening effects in the following order: Ir > Rh > Ni > Pt. The bonding state between Ti and the impurity atom was visually characterized owing to the difference between their charge densities. By integrating the calculations of mean bond length and mean population, the results showed that Ti-Os had the largest mean population and degree of delocalization of the electron cloud around the solute atom, implying ionic characteristics of Os and Ti. Furthermore, after analyzing the alloying elements of each group, we found that VIII-group elements (Ru, Rh, Pd, Os, Ir, Pt) had good potentials for improving the comprehensive mechanical properties of Ti alloys.

Automated summary

This study systematically investigated the effects of 33 alloying elements on the elastic properties and solid solution strengthening (SSS) of alpha-Ti alloys using first-principles calculations. It was found that Ti35Os had the highest elastic modulus, Au, Co, and Pt showed promise in improving the ductilities of alpha-Ti solid solution alloys, and Ir, Rh, Ni, and Pt exhibited the best solid solution hardening effects. The analysis of charge densities revealed the ionic characteristics of Os and Ti in the Ti-Os bonding state. Additionally, VIII-group elements showed potential in enhancing the comprehensive mechanical properties of Ti alloys.