高熵合金的压力诱导多形态研究

High-entropy alloys (HEAs) are currently at the cutting edge of metals research due to their unique chemistry，atomic structure and excellent properties. Very recently, a team led by this applicant discovered a pressure-induced irreversible polymorphic transition in a prototype fcc-structured CoCrFeMnNi HEA using in-situ high pressure synchrotron x-ray diffraction. This result opens up a new avenue towards understanding the atomic structure, phase stability of HEAs and provides a new method for developing novel HEAs. In this proposal, the applicant proposes to integrate multiple in-situ high pressure synchrotron radiation x-ray techniques including x-ray diffraction, emission spectroscopy and imaging for a further systematical investigation of the universality of this polymorphic transition in various HEAs, the key factors which control the transition, the mechanism of the transition, and the atomic structure and properties of new HEAs synthesized via the transition. The results obtained in this proposed project will help to improve our fundamental understanding of HEAs and guide their practical development.

高熵合金由于其独特的化学成分、原子结构和优异的综合性能，成为了金属材料研究的热点前沿。最近，利用高压原位同步辐射x射线衍射技术，申请人在一种典型的面心立方结构的CoCrFeMnNi高熵合金中发现了一个压力诱导的不可逆多形态相变。这一发现为高熵合金的结构、相稳定性、和新材料合成研究开辟了新途径。本项目拟综合利用多种高压原位同步辐射技术(包括衍射、发射光谱学、成像等)，对这类相变的普适性、影响相变的关键因素、相变机理、高压合成的新合金的结构和性能进行深入系统的研究，加深我们对高熵合金结构稳定性的理解和指导新合金的开发。

高熵合金由于其独特的化学成分、原子结构和优异的综合性能，成为了金属材料研究的热点前沿。前期利用高压原位同步辐射x射线衍射技术，项目负责人在一种典型的面心立方结构的CoCrFeMnNi高熵合金中发现了一个压力诱导的不可逆多形态相变。这一发现为高熵合金的结构、相稳定性、和新材料合成研究开辟了新途径。本项目通过综合利用多种高压(高温)原位同步辐射技术(包括衍射、发射光谱学)、高分辨电镜、磁性能表征技术，对这类相变的成分和结构普适性、影响相变的关键因素、微观相变机理、新高熵合金的结构和性能进行了系统深入的研究，在包括fcc，bcc的晶态高熵合金，甚至非金属和金属高熵非晶体系中，发现了丰富的压力结构调控和可逆、不可逆相变现象，加深我们对高熵合金结构稳定性的理解，为新高熵材料的开发提供了指导。