【作者】 张诗昌； 宗钦；

【Author】 ZHANG Shichang ZONG Qin (Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081)

【机构】 武汉科技大学钢铁冶金与资源利用教育部重点实验室；

【摘要】 介绍了 Miguel lagos 等提出的超塑性变形的两相理论以及由 K．Higashi 等提出的高温高应变速率超塑性变形的液膜理论。两相理论从分析材料晶格空位扩散过程出发,建立了超塑性变形条件下应力与应变速率的数学关系。液膜理论指出:高温条件下,材料内部存在一个厚度为几十纳米的液膜层是材料具有高应变速率超塑性的重要原因,并且提出了液相厚度的计算方法。更多还原

【Abstract】 The two-phase theory of superplastic deformation made Miguel lagos and the liquid film theory for the high temperature and high strain rate superplastic flow putted forward by K.Higashi are respectively introduced. By analyzing the diffusion process of vacancies in metallic lattice of material,an equation is deduced in the two-phase theory to describe the relation between stress and strain rate of superplastic deformation.The liquid film theory proves that there exists a liquid film layer with the thickness of dozens of nms at the given elevated temperature and the liquid phase is the key factor that the material has the high strain rate superplasticity.Furthermore,a method is putted for-ward to calculate the thickness of the liquid phase.更多还原