冷旋U-6.5Nb合金再结晶晶粒长大的实验研究

采用冷旋加工-退火工艺细化U-6.5Nb合金晶粒组织，研究旋压变形率、退火温度及退火时间对再结晶后晶粒组织的影响。结果表明，在研究范围内，旋压变形率对晶粒尺寸没有显著影响，随退火温度的升高和退火时间的延长，晶粒尺寸不断长大。在700, 800和900 ℃保温过程中的晶粒长大指数分别为0.47, 0.31和0.34，晶粒长大激活能为100.4 kJ/mol, 表明U-6.5Nb合金的晶粒长大受Nb原子的扩散控制

Experimental Study on Recrystallized Grain Growth of Cold-Spun U-6.5Nb Alloy

A cold spinning-annealing technique was used to refine grains of U-6.5Nb alloy. The effects of reduction ratio, annealing temperature and holding time on the recrystallized microstructures were studied. The results show that grains become coarse when the annealing temperature was increased from 700 oC to 800 oC, and then to 900 oC, while the reduction ratio has no obvious effects on the recrystallized microstructure. The grain growth indexes at 700 oC, 800 oC and 900 oC are 0.47, 0.31 and 0.34, respectively, and the activation energy for grain growth is 100.4 kJ/mol, indicating that the grain growth of U-6.5Nb alloy is a Nb diffusion-controlled process