Effect of Impurities on Superplastic Flow and Cavitation

本研究的目的是研究细晶金属合金中的超塑性流动。重点研究了Zn-22%Al和Pb-62%Sn中晶界杂质原子偏析对蠕变和空化的影响。将特别注意描述造成观察到的蠕变应力阈值的机制，并确定细晶合金中变形和空洞生长之间的关系。预计本研究项目的结果将加强对杂质原子在超塑性合金变形、成形性和断裂中的作用的理解。

The objectives of this research is to study superplastic flow in fine grained metallic alloys. In particular, the effects of impurity atom segregation at the grain boundaries on creep and cavitation in Zn-22%Al and Pb-62%Sn will be investigated. Special attention will be given to delineating the mechanisms responsible for the observed creep stress threshold, and to determining the relationship between deformation and cavity growth in fine grain alloys. It is anticipated that the results of this research program will enhance the understanding of the role of impurity atoms in the deformation, formability, and fracture of superplastic alloys.