X12合金动态再结晶临界应变模型

Critical strain model of dynamic recrystallization of X12 alloy

采用Gleeble-1500D热-力模拟试验机在变形温度950～1200℃,应变速率0.05～5 s^（-1）的条件下对超超临界汽轮机的高、中压转子用X12（X12CrMoWVNbN10-1-1）合金进行了热模拟压缩试验。基于试验所得数据求解加工硬化率,根据lnθ-ε曲线出现的拐点以及-（lnθ）/ε-ε曲线的最小值,建立了X12合金的动态再结晶临界应变模型。研究表明：X12合金的在应变速率为0.05～0.1 s^（-1）、温度为950～1200℃和应变速率为0.5～5 s^（-1）、温度为950～1050℃时发生动态再结晶;临界应变（ε_c）与峰值应变（ε_p）之间呈正比关系ε_c/ε_p=0.69;动态再结晶临界应变模型为ε_c=0.0266Z^（0.0326）。

The thermal compression test of X12（X12 CrMoWVNbN10-1-1） alloy for high and medium pressure rotor of ultra supercritical steam turbine was carried out by using a Gleeble-1500 D thermal-force simulator under the condition of deformation temperature of 950-1200 ℃ and strain rate of 0.05-5 s^（-1）. Based on the experimental data, the work hardening rate of the alloy was obtained. According to the inflection point of the lnθ-ε curve and the minimum value of the-（lnθ）/ε-ε curve, the critical strain model of dynamic recrystallization of the X12 alloy was established. The results show that the dynamic recrystallization of the X12 alloy occurs at the strain rate range of 0.05-0.1 s^（-1） and temperature range of 950-1200 ℃, as well as at the strain rate range of 0.5-5 s^（-1） and temperature range of 950-1050 ℃. The critical strain（ε_c） is proportional to the peak strain（ε_p）, i.e. ε_c/ε_p=0.69, and the critical model of dynamic recrystallization of the X12 alloy is ε_c=0.0266Z^（0.0326）.