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室温下采用等径弯曲通道变形(Equal Channel Angular Pressing,ECAP)Bc路径对纯镍(99.99%)进行8道次挤压变形,然后对其进行压下量为75%的冷轧变形。通过不同的退火试验,研究了ECAP加冷轧变形后退火纯镍的显微硬度和显微组织变化。结果表明:在退火期间组织表现为不连续静态再结晶。当退火温度低于280℃时,试样的显微硬度下降缓慢,组织变化不大;当退火温度高于280℃时,显微硬度迅速下降,组织发生再结晶。再结晶动力学分析表明:当退火温度低于300℃时,样品在退火过程中发生二维生长;当退火温度高于320℃时,发生三维生长。样品再结晶表观激活能经估算约为(77±4)k J/mol,与晶界扩散能几乎保持一致。
Pure nickel (99.99%) was subjected to 8 passes at room temperature using an Equal Channel Angular Pressing (ECAP) Bc path followed by a 75% reduction in cold rolling deformation. Through different annealing tests, the microhardness and microstructure of ECAP annealed pure nickel after cold rolling deformation were studied. The results showed that the microstructure showed discontinuous static recrystallization during annealing. When the annealing temperature is lower than 280 ℃, the microhardness of the sample decreases slowly and the microstructure does not change much. When the annealing temperature is higher than 280 ℃, the microhardness decreases rapidly and the microstructure recrystallizes. The recrystallization kinetics analysis shows that when the annealing temperature is lower than 300 ℃, the samples grow two-dimensionally during the annealing process. When the annealing temperature is higher than 320 ℃, three-dimensional growth occurs. The apparent activation energy of sample recrystallization is estimated to be about (77 ± 4) kJ / mol, which is nearly consistent with the grain boundary diffusion.