Alloy Design of Low-Density Nb-Ti Superalloy Based on d-Electrons Theory

The applicability of the d-electrons theory for designing Nb-base alloys was analyzed. The Md parameter was improved and verified. Furthermore, the low-density Nb-Ti alloy system was calculated and designed. The results show that solid solution W, Mo, Zr, Hf, and Ta are the most effective alloying elements to strengthen the Nb-base alloy. The strengthening effect by adding W element is better than that by the same amount of Mo element. With the increasing of Ti content in Nb-base alloy, the high-temperature strength of the alloy deceases. Considering the alloy density, high-temperature strength, oxidation resistance and other factors, an optimal composition was obtained: 65.95Nb-17Ti-3Al-4Cr-5V-2W-1.5Mo-1.5Hf-0.05C (wt%).