摘 要
高熵合金作为一种新型多主元合金，因其独特的微观结构和优异的性能，近年来在高温材料领域引起了广泛关注。本研究旨在探讨高熵合金在高温环境下的微观结构演变及其稳定性机制。通过结合实验与计算模拟方法，系统分析了不同成分高熵合金在高温下的相变行为、晶格畸变及元素偏析现象。实验中，采用X射线衍射、透射电子显微镜及原子探针层析技术对合金的微观结构进行了详细表征，并结合第一性原理计算揭示了其高温稳定性的内在机理。结果表明，高熵合金在高温下表现出显著的相稳定性，主要归因于其复杂的化学无序结构和多主元协同效应。特别是，某些特定成分的高熵合金在1000℃以上仍能保持单一固溶体结构，展现出优异的高温力学性能和抗氧化能力。此外，研究发现元素间的相互作用对合金的热稳定性具有重要影响，其中Co、Cr元素的添加显著提升了合金的高温抗蠕变性能。本研究不仅为高熵合金的高温应用提供了理论依据，还为其成分设计和性能优化提供了新的思路。
关键词：高熵合金；高温稳定性；微观结构演变；元素偏析
Abstract
As a new type of multi-principal element alloy, high entropy alloy has attracted extensive attention in the field of high temperature materials in recent years because of its unique microstructure and excellent properties. The aim of this study is to investigate the microstructure evolution and stability mechanism of high entropy alloy at high temperature. The phase transition behavior, lattice distortion and element segregation of high entropy alloys with different compositions at high temperature were systematically analyzed by combining experimental and computational simulation methods. In the experiment, the microstructure of the alloy was characterized by X-ray diffraction, transmission electron microscopy and atomic probe chromatography, and the internal mechanism of high temperature stability was revealed by first principles calculation. The results show that the high entropy alloy exhibits remarkable phase stability at high temperature, which is mainly attributed to its complex chemical disordered structure and multi-principal component synergistic effect. In particular, some high-entropy alloys with specific compositions can still maintain a single solid solution structure above 1000℃, showing excellent high temperature mechanical properties and oxidation resistance. In addition, it is found that the interaction between the elements has an important effect on the thermal stability of the alloy, in which the addition of Co and Cr elements significantly improves the high temperature creep resistance of the alloy. This study not only provides a theoretical basis for the application of high entropy alloy at high temperature, but also provides a new idea for its composition design and performance optimization.
Keywords： High Entropy Alloy; High Temperature Stability; Microstructure Evolution; Element Segregation
目 录
摘要 I
Abstract II
一、引言 1
二、高熵合金的微观结构特征分析 2
（一）高熵合金的晶体结构类型 2
（二）高熵合金的相形成机制 2
（三）高熵合金的元素分布与偏析行为 3
三、高温环境下高熵合金的稳定性研究 4
（一）高温下高熵合金的相稳定性分析 4
（二）高温氧化行为及其对稳定性的影响 5
（三）热膨胀与热导率的高温特性 5
四、高熵合金微观结构与高温稳定性的关联性分析 7
（一）微观结构对高温力学性能的影响 7
（二）界面结构与高温稳定性的关系 7
（三）元素分布对高温抗氧化性能的作用 8
结 论 9
参考文献 10
