The Influence of Trace Elements on High Temperature Intergranular Fracture

该项目旨在确定小的影响， 合金元素对高温蠕变机制的影响 空穴和沿晶断裂。 一个模型镍-20% 含有微量添加的铈，硼， 锆和镁将用于本研究。 具体 研究目标包括：（1）确定 微量元素对高温蠕变流动，空穴成核， 沿晶断裂和延性;（2）测定 动力学、晶界滑动机制和应力机制 用内摩擦法测定松弛现象.测量 空穴成核率和相关参数的变化， 测定表面自由能。 结果将 分析并比较了空穴形核、蠕变 断裂时间和延展性。

This project is designed to determine the effects of small alloying additions on the mechanism of high temperature creep cavitation and intergranular fracture. A model nickel-20% chromium alloy containing trace additions of cerium, boron, zirconium and magnesium will be used in this study. The specific research objectives include: (1) determination of the effects of trace elements on high temperature creep flow, cavity nucleation, intergranular fracture, and ductility; (2) determination of kinetics, mechanisms of grain boundary sliding and of stress relaxation phenomena by means of internal friction; measurement of cavity nucleation rates and associated parameters particularly with determination of surface free energies. The results will be analyzed and compared to models of cavity nucleation, creep rupture time and ductility.