Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8003116 | Journal of Alloys and Compounds | 2013 | 7 Pages |
Abstract
Evolution of the secondary α phase morphologies during isothermal heat treatment of a near β titanium alloy Ti-7Mo-3Al-3Nb-3Cr (Ti-7333) has been studied by using SEM and TEM. The results indicated that the morphologies of α phase widely varied by changing the isothermal temperature and time. The needle-like secondary α precipitate morphology formed after solution treatment above β transus followed with aging treatment. When the aging temperature reduced, the length and width of α phase reduced while the volume fraction increased. This increasing in the volume fraction of α phase resulted in the strengthening of the micro-hardness of the alloy. In addition, the results showed that there was almost no precipitation after 1 min isothermal holding time at 650 °C. After 2 min, α phase presented a dot shape precipitation with a nonuniform distribution. Increasing the holding time to 5 min, the α precipitation demonstrated a needle-like shape. At last, the coarse α precipitation formed after aging 3 h. The volume fraction of α increased from 4.6% to 44% while the aging time increasing from 2 min to 3 h. The effect of the alloy elements on governing the microstructure is discussed.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Xue Zhang, Hongchao Kou, Jinshan Li, Fengshou Zhang, Lian Zhou,