【摘要】 采用电子背散射衍射(EBSD)技术研究了黄铜H68初始样品经6%轧制后在650℃退火不同时间的晶界特征分布(GBCD)。结果表明:特殊晶界比例随退火时间增加而增大,退火10 min时达到峰值76%;同时互成Σ3n(n=1,2,3)界面关系的特殊晶粒团平均尺寸超过300μm,使外围的一般大角晶界网络连通性被阻断,实现了GBCD的优化。分析指出:退火中非共格∑3晶界优先在三叉晶界(triple junctions)处形核并在界面应力(SIBM)作用下迁移,迁移中发生∑3n(n=1,2,3)晶界的交互反应,这可能是样品晶界特征分布随退火时间演化的主要机制。更多还原

【Abstract】 The grain boundary character distributions( GBCD) of a brass H68 alloy rolled with strain of 6%( thickness reduction) and then annealed at 650 ℃ for different time were studied by means of electron back scatter diffraction( EBSD).The results show that the fraction of special boundaries( fSBs) increases with the increasing annealing time.A peak value( 76%) of fSBsis obtained when annealing time reaches 10 min.In the meanwhile,the averaged size of the cluster of grains interfaced by Σ3n( n =1,2,3) boundaries exceedes300 μm and the connectivity of random grain boundary network is effectively interrupted by SBs,indicating optimized GBCDs have been achieved.Further analysis points out that the nucleation of incoherent ∑3 boundaries( ∑3ic) in the triple junctions,and subsequent strain-induced migration of ∑3icand interaction among ∑3n( n =1,2,3) boundaries during annealing might be the operative mechanism for GBCD optimization.更多还原