【摘要】 采用电子背散射衍射(EBSD)技术研究了不同温度轧制黄铜H68样品退火后的晶界特征分布(GBCD)。黄铜H68再结晶样品在不同温度下(-20℃、室温、100℃)进行6%轧制,随后进行650℃×10 min退火处理。结果表明:在室温下轧制退火比在100℃轧制退火和-20℃轧制退火生成更高比例的特殊晶界,其值达到78.7%;较大尺寸(400μm)的∑3n(n=1,2,3)特殊晶粒团使外围的一般大角晶界网络连通性被阻断,实现了合金的GBCD优化。分析指出:在室温下轧制,合金的层错能有利于后续退火中形成退火孪晶,并发生Σ3n(n=1,2,3)晶界迁移与交互反应;在100℃下轧制,合金的层错能较高,有利于后续退火中生成一般大角度晶界包围的新生晶粒;在-20℃下轧制,合金的层错能较低,后续退火中晶界迁移的驱动力不足,不能实现GBCD优化。更多还原

【Abstract】 A recrystallized brass H68 alloy was rolled with strain of 6%(thickness reduction) at different temperatures(-20 ℃,room temperature and 100 ℃) and then annealed at 650 ℃ for 10 min.The grain boundary character distributions(GBCD) in the processed samples were studied by means of electron back scatter diffraction(EBSD) technigne.The results show that the fraction of special grain boundaries of brass H68 samples annealed after rolling at room temperature is higher than those annealed after rolling at-20 ℃ and 100 ℃.The fraction of total special boundaries reaches 78.7%.The averaged size of the clusters of grains bounded by ∑3n(n = 1,2,3) special boundaries is larger than 400 μm and the connectivity of general high angle boundaries(HABs) networks is interrupted sufficiently by the special boundaries,which indicated that GBCD optimization is obtained.It is pointed out that,stacking fault energy(SFE) is favorable to introducing annealing twins and interactions among Σ3n(n =1,2,3) boundaries via their migrations in the annealed specimen rolled at room temperature.However,the optimization of GBCD is not achieved in both annealed specimens previously rolled at 100℃ and-20 ℃.Increased SFE at 100 ℃ led to newly-formed grains enclosed by random high angle grain boundaries rather than Σ3n(n =1,2,3) boundaries,and the reduced SFE at-20 ℃ provided insufficient driving force for grain boundaries and therefore led to an undesirable GBCD in the subsequently annealed specimens.更多还原