DP处理GH4169合金的热变形行为

Hot Deformation Behavior of δ Processed GH4169 Alloy

摘要:

优质GH4169镍基高温合金的Nb含量较高，热变形工艺参数需严格控制，特别是经δ 相时效处理(Delta Processed，DP)后，因此有必要对其热变形行为进行研究。本文对经DP处理后的优质GH4169高温合金在不同变形温度 (980，1010，1040和1070°C)及应变速率 (0.001，0.01，0.1和1 s-1)进行热模拟压缩实验。结果表明： GH4169镍基高温合金在该变形条件下的平均激活能Q = 528.24 kJ/mol，Nb元素含量上调会显著增加合金的变形激活能(约40 kJ/mol)，该材料的热变形过程可通过双曲正弦本构模型进行描述。通过表征相应热变形后的显微组织，结合GH4169高温合金的热加工图，表明GH4169高温合金适宜在低温低应变速率和高温高应变速率下加工。

Abstract:

The high-quality GH4169 nickel-base superalloy has higher Nb content, and its microstructure is more sensitive to the process parameters,especially after δ phase aging (DP) treatment, thus it is necessary to study its hot deformation behavior. In this paper, the hot deformation behavior of GH4169 alloy, have been studied by isothermal compression tests at the temperatures of 980-1070°C and strain rates of 0.001-1 s-1. The results show that the deformation temperature and the strain rate have obvious effects on the flow characteristic. Constitutive model was established based on sine-hyperbolic Arrhenius kinetic rate equation, the value of average activation energy ( 528.24 kJ/mol) of GH4169 alloy is obtained in present study,increase of Nb content will increase the modified activation energy significantly. Hot workability is interpreted by processing maps. The optimum hot working conditions for GH4169 ally was low temperature with low strain rate and high temperature with high strain rate area.