High Temperature Creep Properties of Ordered Nickel-Aluminum Alloys

本课题主要研究掺硼镍铝的高温变形问题。研究高温蠕变和超塑性变形的基本机理。这种材料的屈服强度不寻常的温度依赖性，即随温度升高而增加的屈服强度达到最大值，使其成为高温应用的特别有趣的材料。引起蠕变和超塑性行为的机制尚不清楚。有序晶格的性质，包括反相边界能的各向异性和交叉滑移过程的细节，使其蠕变性能与在固溶体合金中观察到的完全不同。本项目将研究该有序合金高温变形速率控制的微观机制。

This research program addresses the high temperature deformation of boron-doped nickel aluminide. Fundamental mechanisms responsible for high temperature creep and superplastic deformation will be studied. The unusual temperature dependence of the yield strength of this material, i.e., an increasing yield strength with increasing temperature up to a maximum, makes it a particularly interesting material for high temperature applications. Mechanisms causing creep and superplastic behavior are not well understood. The nature of the ordered lattice, including anisotropy of antiphase boundary energy and details of the cross- slip process, make the creep properties quite different from those observed in solid solution alloys. This project will investigate the rate-controlling micromechanisms of elevated temperature deformation in this ordered alloy.