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对FGH4096合金进行了变形温度1050～1140℃,应变速率0.001～2s-1的热压缩实验。分析了合金的流变行为,构建了Arrhenius型本构方程,得到合金的热变形激活能为870.785kJ/mol。并建立了能够准确描述热加工过程中能量耗散情况和预测变形失稳的热加工图。结果表明:能量耗散与动态再结晶和晶粒长大有关,在变形温度Td为1050～1070℃,应变速率ε为0.001～0.01s-1范围内,峰值耗散率为61%(1050℃,0.001s-1),此区域易形成“项链”组织,很多晶粒处于形核阶段;在Td为1100～1140℃,ε为0.001～0.01s-1范围内,能量耗散峰值达50%(1110℃,0.001s-1),此时,晶界迁移显著,再结晶晶粒明显长大;在Td为1070～1100℃,ε为0.01～0.1s-1范围内,能量耗散率大于39%左右,再结晶完全、晶粒细小。Td为1060～1100℃,ε为0.5～2s-1时,合金落入流变失稳区,能量耗散率达到最小值,局部变形严重是造成流变失稳的重要原因。
The FGH4096 alloy was subjected to hot compression test with deformation temperature of 1050 ~ 1140 ℃ and strain rate of 0.001 ~ 2s-1. The rheological behavior of the alloy was analyzed and the Arrhenius type constitutive equation was constructed. The thermal deformation activation energy of the alloy was 870.785kJ / mol. And established a thermal processing diagram that accurately describes the energy dissipation during thermal processing and predicts the deformation instability. The results show that the energy dissipation is related to the dynamic recrystallization and grain growth. The peak dissipation rate is 61% (1050 ℃) at deformation temperature Td of 1050 ~ 1070 ℃ and strain rate ε of 0.001 ~ 0.01s-1 , 0.001s-1). In this region, “necklace ” structure is easily formed, and many grains are in the nucleation stage. At the Td of 1100 ~ 1140 ℃ and ε of 0.001 ~ 0.01s-1, 50% (1110 ℃, 0.001s-1). At this time, the grain boundary migrated significantly and the recrystallized grains grew obviously. At Td of 1070-1100 ℃ and ε of 0.01-0.1 s-1, the energy dissipation More than 39% rate, recrystallization complete, small grains. When the Td is 1060 ~ 1100 ℃ and ε is 0.5 ~ 2s-1, the alloy falls into the rheological instability zone, and the energy dissipation rate reaches the minimum value. The serious local deformation is the important reason for the rheological instability.