【摘要】 材料高温性能测试与表征是当前高温固体力学发展所面临的挑战之一，开展原位高温力学实验对研究材料显微变形及微结构演化具有重要意义。本文基于光学显微成像原理建立了一套原位高温力学测量系统，通过该系统可进行室温至1000℃的常压或真空环境下的原位拉伸、疲劳和蠕变的力学性能测量。首先，采用标准7075铝合金进行单轴拉伸和疲劳实验，验证了该测量系统加载的稳定性。然后，采用镍基单晶合金开展原位高温成像实验，分析了热源温度特性及原位高温成像的质量。最后，利用本文系统在900℃下对镍基单晶合金进行原位单轴拉伸与疲劳实验，实时观测了加载过程中的裂纹萌生、扩展及微孔洞的演化行为。实验结果表明，本文所建立的原位高温力学测量系统可实现对被测试样的稳定加载及光学显微的原位清晰成像，并可为揭示高温合金的宏观力学性能与其微结构演化之间的关联机制提供有效的实验平台。更多还原

【Abstract】 The testing and characterisation of high-temperature properties of materials are one of the current challenges in the development of high-temperature solid mechanics, and it is of great significance to carry out in-situ high-temperature mechanical experiments to study their micro-deformation as well as microstructural evolution. In this paper, a set of in situ high-temperature mechanical measurement systems is established based on optical micro-imaging, which can carry out in-situ tensile, fatigue and creep mechanical property measurements under atmospheric pressure or vacuum environments from room temperature to 1000 ℃. Firstly, uniaxial tensile and fatigue experiments were carried out using standard 7075 aluminum alloy to verify the loading stability of the measurement system. Second, in-situ high-temperature imaging experiments were carried out using a nickel-based single-crystal alloy, and analyses of the temperature characteristics of the heat source as well as the quality of the in situ high-temperature imaging were carried out. The results show that the measurement system can achieve stable loading of the test specimen and clear in-situ imaging of optical microscopy. Finally, in-situ uniaxial tensile and fatigue experiments of nickel-based single crystal alloys were completed at 900 ℃ with the help of the measurement system, and the crack initiation, propagation and microporous evolution were observed in real-time during the loading process, which provided an effective experimental platform to reveal the correlation mechanism between the macro-mechanical properties of high-temperature alloys and their microstructural evolution.更多还原