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随着新一代低油耗和高推重比航空发动机的发展,对新型涡轮盘合金提出了更高的要求。FGH4096是典型第二代高强和高损伤容限型涡轮盘合金,长期使用温度为700~750℃,采用粉末冶金(P/M)工艺制备。本文采用电渣重熔连续定向凝固(ESR-CDS)技术和多向锻造技术制备了低偏析的FGH96合金(命名为CDS&W FGH96)锻坯,通过等温热压缩实验研究了锻态合金在温度范围为1060~1140℃,应变速率范围为0.001~0.100 s-1的热变形特点。结果表明,随着温度的增加,再结晶(DRX)分数先减小后增加;弥散细小的γ’相颗粒阻碍动态再结晶形核,而尺寸较大的相颗粒在一定程度上可大大降低对动态再结晶的这种阻碍作用;动态再结晶晶粒尺寸随着变形温度的降低而降低。通过流变行为计算得到热变形激活能为1289 k J·mol-1,并提出了合金CDS&W FGH96高温变形本构方程。借助于场发射扫描电镜(FESEM)和透射电镜(TEM)阐述了动态再结晶机制为应变诱导原始晶界形核和第二相位错塞积形核。
With the new generation of low fuel consumption and high thrust than the development of aeroengine, the new turbine disk alloy put forward higher requirements. FGH4096 is a typical second generation high strength and high damage tolerance turbine disk alloy, long-term use temperature of 700 ~ 750 ℃, the use of powder metallurgy (P / M) process preparation. In this paper, low segregation FGH96 alloy (named as CDS & W FGH96) was prepared by ESR-CDS and multi-directional forging technology. The isothermal hot compression experiments were carried out to study the mechanical properties of as-forged alloy in the temperature range 1060 ~ 1140 ℃, the strain rate range of 0.001 ~ 0.100 s-1 thermal deformation characteristics. The results show that with the increase of temperature, the recrystallization (DRX) fraction first decreases and then increases. The dispersed fine γ ’phase particles impede the dynamic recrystallization nucleation, while the larger size phase particles can reduce to a certain extent Dynamic recrystallization of this obstruction; dynamic recrystallization grain size decreases with the deformation temperature decreases. The activation energy of thermal deformation was calculated to be 1289 kJ · mol-1 by rheological behavior and the constitutive equation of high temperature deformation of alloy CDS & W FGH96 was proposed. The dynamic recrystallization mechanism is described as strain induced primary grain boundary nucleation and second phase mismatch sedimentation by means of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM).