The composition of the alloy fundamentally determines the performance of the alloy. With the increasing requirements on the material performance and the change of the material design concept, people have carried out different degrees of composition optimization and redesign of Gr5 titanium alloy to meet different requirements.

There are many re-designs for composition optimization of Gr5, such as the early TImetaL 62S(Ti-6al-2FE-0.1 Si), Ti8LC (Ti-al-Fe-Mo), Ti12LC(Ti-al-Fe-Mo) and so on. In recent years, TImetaL CL4(Ti-5al-3V-0.6 Fe-0.1O), ATI 425(Ti-4al-2.5V-1.5FE-0.25O), Ti575(Ti-5.3 al-7.7V-0.5 Si) Ti-54m (Ti-5al-4V-0.75 Mo-0.5Fe), Ti407(Ti-0.85 al-3.7V-0.25 Fe-0.25Si) and other modified Titanium alloys with Gr5 have been successively developed.

There are two main purposes for Gr5 modification. One is for performance consideration, especially its dynamic mechanical properties. For example, Ti575 alloy reduces Al equivalent and increases Mo equivalent compared to Gr5, and a small amount of Si is added to improve the strength of the alloy. Its tensile strength and yield strength are both higher than Gr5, and at the tensile strength of 1200 MPa, the elongation can reach 10.5%, 8% higher than Gr5. And compared with Gr5 alloy, the alloy has better fatigue performance and malleability.

Another aim for the Gr5 variant is to reduce costs. TImetaL CL4 and ATI 425 both reduce the content of Al and V and add a certain amount of Fe and O elements on the basis of Gr5, which not only ensures the strength, but also improves the cold processing property of Gr5 alloy, thus reducing the cost. Ti407 alloy has a lower Al equivalent and improves machining performance by sacrificing material strength. The alloy is designed to partially replace Gr5 and reduce the cost of materials for commercial aircraft. Ti-54m has a lower Al equivalent than Gr5, and a small amount of Mo and Fe elements are added to reduce the transition temperature. Compared with Gr5, this alloy has better processability and formability, and its superplastic forming ability is better than Gr5 material, which can significantly reduce the processing cost.