In this paper, the dynamic mechanical properties of GH4720Li nickel-base alloy under a large temperature range and high and low strain rates were studied by the hot compression test. The difference of mechanical properties of GH4720Li alloy under high and low strain rates was analyzed from the perspective of microstructure. The hot compression test experimental results showed that the true stress of GH4720Li alloy decreased at a low strain rate as the trial temperature elevated. Nevertheless, it was abnormal that the true stress increased at high strain rate condition as temperature elevated. By comparing the microstructure under high and low strain rates, it was found that the precipitates under low strain conditions contained a large amount of Cr (Mo). However, the content of Cr (Mo) in the precipitates at a high strain rate decreased, while the content of Fe increased. It would be concluded that Cr (Mo) would reduce the compressive strength and plasticity of GH4720Li alloy, while Fe would increase the compressive strength and plasticity of GH4720Li alloy. In addition, under the condition of a low strain rate, the shape of Cr (Mo) precipitates obtained at 20°C was lamellar, but it was spherical at 800°C. The compressive strength of GH4720Li composites with lamellar precipitates was higher than that of spherical precipitates.

中文翻译：

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GH4720Li在较宽温度范围内高应变速率下的力学性能研究

通过热压缩试验研究了GH4720Li镍基合金在大温度范围和高低应变速率下的动态力学性能。从微观结构的角度分析了GH4720Li合金在高应变率和低应变率下的力学性能差异。热压缩实验结果表明，随着试验温度的升高，GH4720Li合金的真实应力在低应变率下降低。然而，在高应变速率条件下，随着温度升高，真实应力增加是异常的。通过比较高应变率和低应变率下的显微组织，发现低应变条件下的析出物中含有大量的Cr（Mo）。但是，高应变速率下析出物中的Cr（Mo）含量降低，而Fe的含量增加。可以得出结论，Cr（Mo）会降低GH4720Li合金的抗压强度和塑性，而Fe会增加GH4720Li合金的抗压强度和塑性。另外，在低应变速率的条件下，在20℃下获得的Cr（Mo）析出物的形状为层状，而在800℃下为球形。层状沉淀物的GH4720Li复合材料的抗压强度高于球形沉淀物。但在800°C时呈球形。层状沉淀物的GH4720Li复合材料的抗压强度高于球形沉淀物。但在800°C时呈球形。层状沉淀物的GH4720Li复合材料的抗压强度高于球形沉淀物。