合金元素Cr和V对Ti-45Al-8Nb合金定向凝固组织的影响

In this paper,the directional solidification of Ti-45Al-8Nb，Ti-45Al-8Nb-1.0Cr，Ti-45Al-8Nb-2.5V and Ti-45Al-8Nb-1.0Cr-2.5V alloys were carried out through Bridgman method. The results shows that all of the four alloys obtained single crystal with the angle of lamellar orientation and growth direction being 45 , and the Ti-45Al-8Nb-1.0Cr-2.5V alloy obtains the single crystal fastest. Both Cr and V can refine the lamellar microstructure, and the average lamellar spacing of the Ti-45Al-8Nb-1.0Cr-2.5V alloy is only 53% of that of the Ti-45Al-8Nb alloy. Cr and V are only found in the γ lamellar and make the Al content of the α2 lamellar increase. The alloy elements addition are harmful to the hardness.