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超细晶/纳米晶金属材料具有优异的力学性能,广泛应用于航天、航空、机械、电气、医学等领域。蠕变经常是在高应力或高温下工作的零部件失效模型的主要变形机制之一,因此对蠕变行为进行系统深入的研究是非常必要的。近年来,蠕变形为研究也成为了超细晶/纳米晶金属材料领域的一个重要发展方向。本文综述了纳米粉末合成、电解沉积和剧烈塑性变形制备的超细晶/纳米晶金属材料的蠕变行为研究进展。介绍了蠕变性能研究的主要方法——单轴蠕变试验和纳米压痕蠕变试验,对比了两种试验方法的测试数据。重点从稳态蠕变应力指数、蠕变激活能和蠕变应变速率方面论述了纳米粉末合成、电解沉积和剧烈塑性变形制备的超细晶/纳米晶金属材料的蠕变行为,分析了超细晶/纳米晶金属材料的晶界滑动和晶界扩散蠕变机制以及位错运动蠕变机制,同时进一步指出蠕变行为及机制研究中存在的问题及发展趋势。
Ultrafine crystal / nanocrystalline metal materials with excellent mechanical properties, widely used in aerospace, aviation, machinery, electrical, medical and other fields. Creep is often one of the major deformation mechanisms for failure modes of components that work under high stress or high temperature. Therefore, it is necessary to study the creep behavior systematically. In recent years, the study of creep deformation has also become an important development direction in the field of ultra-fine grain / nanocrystalline metal materials. In this paper, the progress in the creep behavior of ultrafine-grained / nanocrystalline metallic materials prepared by nano-powder synthesis, electrodeposition and severe plastic deformation are reviewed. The main methods of creep property research are introduced - uniaxial creep test and nanoindentation creep test, and the test data of two test methods are compared. In this paper, the creep behaviors of ultrafine-grained / nanocrystalline metal materials prepared by nanometer powder synthesis, electrodeposition and severe plastic deformation are discussed from the aspects of steady-state creep stress index, creep activation energy and creep strain rate. The grain boundary sliding and grain boundary creep mechanism of the crystal / nanocrystalline metal material and the creep mechanism of dislocation movement, and further pointed out the problems and trends in the study of creep behavior and mechanism.