The effect of phase stability on the grain growth behavior of beta titanium alloys

摘要

The grain growth kinetics of two beta titanium alloys, Ti-4733 and Ti-5553 was studied over a temperature range of 850 degrees C-1000 degrees C. The more stable alloy i.e. Ti-4733, showed a smaller average grain size and slower growth rate compared to Ti-5553 at a same annealing condition. The results showed that the uniformity of grain size decreased initially dawn to a minimum and then increased with increasing temperature. The grain growth exponent (n) and activation energy (Q) were calculated and it was revealed that n is mainly affected by temperature and Q is generally influenced by time. The n value for Ti-4733 was found to be lower than that for Ti-5553 while a higher Q was calculated for Ti-4733. The lower n values and the higher Q were attributed to the solute drag effect and the high Mo content with low diffusivity in Ti matrix.