FGHxx粉末高温合金疲劳损伤行为表征、评价与展望

FGHxx系列结构材料是我国近年来成功开发的损伤容限型粉末高温合金，由FGH95到FGH99系列，主要是通过材料的化学成分、制粉工艺及后续的热处理工艺参数等优化措施，达到提高在役温度下的强度、韧性性能，改善疲劳裂纹扩展阻力等目的。相比于材料工艺力学的现有研究成果，该系列材料在固体力学相关的疲劳损伤表征、寿命评价、微结构对疲劳裂纹萌生行为的研究存在显著滞后，尤其在损伤容限相关的关键科学问题以及工程关注的安全评估手段等有待深入探究。本文基于作者们对现有的FGHxx系列粉末高温合金疲劳损伤研究现状和关键科学问题的掌握和理解以及对应的部分实验研究结果，从材料微结构特征、疲劳数据分散特点、宏微观疲劳裂纹扩展行为、SEM原位测试、疲劳寿命预测模型、疲劳损伤安全区（三维K-T关系图）的建立等进行了评述和展望。

Characterization,evaluation and expectation of fatigue damage behavior for series PM nickel-based superalloys (FGHxx)

Series powder metallurgy (P/M) nickel-based superalloys (FGHxx) are one of main high temperature structures materials as Chinese damage tolerance P/M superalloys which consisted of FGH95, FGH96 and FGH97 etc.. It is the primary purpose that the service temperature strength, fracture toughness and resistances of fatigue cracking behaviors of P/M superalloys can be effectively enhanced in lower cost through the optimization of the processing parameters including the powder size or other parameters. In this article, the microstructure characteristics, fatigue data scatter peculiarity in S-N curves, fatigue crack initiation and propagation behavior, SEM in-situ testing technology, predication models of fatigue life, fatigue limit, notch factor Kt of 3D K-T diagram were established. And the relative influence factors of series FGHxx superalloys were analyzed and discussed in detail based on the research status including our latest findings.