Grain boundary microstructure-controlled superplasticity in Al-Li-Cu-Mg-Zr alloy
Grain boundary microstructure-controlled superplasticity in Al-Li-Cu-Mg-Zr alloy
复制标题
Al-Li-Cu-Mg-Zr 合金晶界微观结构控制的超塑性
DOI：
10.2320/matertrans.44.1469
复制
发表时间：
2003
影响因子：
1.2
通讯作者：
J. Cui
中科院分区：
文献类型：
--
作者：
S. Kobayashi;T. Yoshimura;S. Tsurekawa;Tadao Watanabe;J. Cui
本文在对不同晶界组织的Al-Li合金试样进行光学显微镜观察的基础上，讨论了晶界组织控制的Al-Li合金超塑性。具有均匀{110}织构晶粒和高频率的小角度晶界的试样显示出超塑性，而具有非均匀和随机取向晶粒和高频率的随机晶界的试样不产生超塑性。空腔优先形成在两个或三个随机边界相互连接的三重连接处。结合晶界特征分布（GBCD）与三结点特征分布的关系，讨论了超塑性的最佳晶界组织。在变形过程中进行应变速率变化试验，以恢复最初引入的最佳晶界显微组织。应变速率变化试验可提高超塑性，使变形软化初期小角度晶界出现的频率增加。
Grain boundary microstructure-controlled superplasticity in an Al–Li alloy is discussed on the basis of OIM observations using the specimens with different grain boundary microstructures. The specimens having the homogeneous {110} textured grains with a high frequency of low-angle boundaries showed superplasticity, whereas the specimen having a heterogeneous and randomly oriented grains with a high frequency of random boundaries did not yield superplasticity. Cavities were preferentially formed at the triple junctions where two or three random boundaries interconnected. From those results, the optimum grain boundary microstructure for superplasticity is discussed in connection with the relationship between grain boundary character distribution (GBCD) and triple junction character distribution. The strain rate change tests were carried out during deformation in order to rejuvenate initially introduced optimal grain boundary microstructure. The superplasticity can be improved by the strain rate change test resulting in an increase of the frequency of low angle boundaries at the early work softening stage of deformation.