中文摘要：

采用Gleeble-1500D热模拟机对GH4742高温合金进行高温压缩试验，观察该合金的金相组织和TEM显微组织并进行对比分析，研究该合金的动态再结晶行为。结果表明：小应变速率、大变形程度及高变形温度均促进了该合金动态再结晶的进行，第二相粒子通过影响位错的运动来影响合金的动态再结晶行为；晶界弓出机制是GH4742高温合金动态再结晶的主要形核方式，部分孪晶通过叠加方式形核；通过对真应力-真应变曲线数据的计算拟合，构建了GH4742高温合金动态再结晶模型。

英文摘要：

Hot compression tests of GH4742 superalloy were conducted on a Gleeble-1500D thermal simulating tester. Metallographs and TEM images were observed and compared, and dynamical recrystallization behavior was investigated. The results show that the dynamical recrystallization （DRX） of the alloy is promoted when the strain rate is small, the true strain is big and the temperature is high. The DRX behavior is affected by the second phase through which the movement of dislocation is influenced. The main nucleation mechanism of DRX in the present alloy is grain boundary bowing nucleation and the other nucleation mechanism is twin superposition nucleation. The DRX modeling of this alloy is established by means of mathematic fitting data based on true stress-true strain curves.