Selection of key alloying elements for improving the elastic modulus of titanium alloys based on feature screening methods

Abstract

Under the background of modern industrial lightweighting and high performance, the low elastic modulus of titanium alloys has become a key issue restricting their structural efficiency and load-bearing capacity. This study conducted feature screening on a small sample dataset, identifying the mean of atomic energy of the ground state (Fm1), the mean of a-lattice constant (Fm29), the mean of nuclear charge number (Fm40), and the variance of melting enthalpy (Fv43) as the four key features affecting the elastic modulus. The prediction accuracy R² of the best model reached 0.96, and a mathematical expression linking the modulus to these four key alloy factors was established using symbolic regression algorithms, achieving a direct correlation between input and target performance. Experimental verification revealed that, in addition to B and Si enhancing the modulus of titanium alloys, the element Ga can also significantly improve the modulus of titanium alloys. Alloys with elastic modulus exceeding 135 GPa were successfully prepared, achieving an increase of over 25 % in elastic modulus compared to TC4 alloy. Further research indicates that the high modulus properties of titanium alloys are primarily attributed to the precipitation of high-modulus second phases α₂, TiB, and Ti₅Si₃ in the microstructure.