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热挤压态FGH95合金热变形特性

Hot deformation characteristics of hot extruded FGH95 superalloys

  • 摘要: 采用Gleeble 3800D热模拟压缩试验机系统地研究了挤压态FGH95合金在变形温度1050~1120 ℃、应变速率0.001~1.000 s−1条件下的热压缩变形行为,获得了挤压态FGH95合金的应力应变曲线,建立了挤压态FGH95合金的本构方程,并基于动态材料模型,绘制了合金的热加工图。结果表明,挤压态FGH95合金的热变形本构方程高温材料常数分别为热变形激活能Q=300.925 kJ·mol−1,常数α=0.01139 MPa−1,参数n=1.86。相较于热等静压态,挤压态合金激活能下降50%以上。根据热加工图能量耗散效率并结合微观组织分析,找到了挤压态FGH95合金的加工安全区和失稳区,提出了热加工工艺参数范围:应变速率为0.010~0.100 s−1,变形温度为1050~1120 ℃。

     

    Abstract: The thermal compression deformation behaviors of the hot extruded (HEX) FGH95 alloys were investigated systematically using the Gleeble 3800D thermal-mechanical simulator in the strain rate of 0.001~1.000 s−1 at the deformation temperature range of 1050~1120 ℃. The constitutive equations of the hot extruded FGH95 alloys were derived from the stress-strain curves obtained in the isothermal compression tests. Furthermore, the hot processing maps were established based on the dynamic models. In the results, the corresponding material constants of the constitutive equation are determined as Q=300.925 kJ·mol−1, α=0.01139 MPa−1, and n=1.86. Compared with the hot isostatic pressing (HIP) alloys, the activation energy of the hot extruded FGH95 alloys is declined by more than 50%. According to the energy dissipation efficiency and the microstructure analysis of the hot extruded FGH95 alloys, the processing safety zone and instability zone are identified during the hot extrusion process. Ultimately, the optimal processing conditions of the FGH95 alloys are proposed as the strain rate of 0.010~0.100 s−1 and the deformation temperature of 1050~1120 ℃.

     

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