超高纯银静态再结晶组织演变规律的研究

Research on Static Recrystallization Microstructure Evolution of Super High-purity Silver

采用超高纯银（纯度高于99.999％）铸锭,通过轧制变形,结合后续不同热处理工艺,研究了变形量、退火温度及时间对超高纯银回复及再结晶组织的影响.结果表明：超高纯银的再结晶温度非常低,在100℃时保温5 min后即发生再结晶,并且再结晶速度快,在200℃下保温5 min即完成再结晶.随轧制总变形量增加晶粒尺寸变小,均匀性提高,当变形量大于等于85％时,可以得到均匀、细化的再结晶组织;超高纯银的最佳再结晶温度应控制在150℃,时间为1～2 h之间.

The super high-purity silver ingot （Purity＞99.999％） prepared by vacuum induction melting,then treated by cold rolling with various deform ratio incorporated with subsequent annealing at different heat treatment,the effects of various deform ratio and annealing methods on the recrystallization behavior are studied.The results revealed that,the initiation temperature of recrystallization of super high-purity silver was low the recrystallization started while annealing at 100 ℃ for 5 min.It also indicated that the recrystallization rate in super high-purity silver is very high,samples recrystallized completely as annealing at 200 ℃ with 5 min.With the increasing of deformation amount,the size of recrystallized grains is gradually refined.The cold-rolling samples with 85 ％ deform ratio have better uniformity.The reasonable annealing process of super high-purity silver is 150 ℃ with 1-2 h.