材料期刊网

在Gleeble--1500热模拟机上对15Cr--25Ni--Fe基合金GH2674进行了热压缩实验,采用动态材料模型的加工图研究了其在950---1200℃和0.001---10 s-1条件下的热变形行为. 结果表明: GH2674合金在热变形时呈现两个微观机制不同的动态再结晶峰区. 再结晶I区: 功率耗散效率峰值为38%,峰值对应的温度和应变速率分别为1040℃与10 s-1;再结晶II区: 功率耗散效率峰值为40%, 峰值对应的温度和应变速率分别为1075℃与0.04 s-1. 在1075-1100℃温度区间内, 可能是晶界相M3B2的溶解造成该合金的晶粒粗化, 这在一定程度上会影响合金的热加工性能. 在应变速率小于0.01 s-1、形变温度高于1050℃条件下, 合金呈现晶粒急剧粗化现象, 进而导致在热变形过程中楔形裂纹的产生; 在应变速率高于0.1 s-1、形变温度低于1000℃条件下, 合金有出现剪切变形带的趋势. 根据上述加工图对GH2674合金的热变形工艺进行了初步设计.

The hot deformation behavior of GH2674 has been studied in the temperature range 950-1200℃ and strain rate range 0.001-10 s-1, using hot compressing testing on a Gleeble-1500 simulator. A processing map is developed on the basis of these data and using the principles of dynamic material modeling. The map exhibits two domains: one at 1050℃ and 0.01 s-1, with a peak efficiency of power dissipation of 38%, the second at 1150℃ and 10s-1, with a peak efficiency of 40%. On the basis of optical microscopic observations, these they are interpreted to represent two dynamic recrystallization(DRX) domains, of which the mechanisms are different. The map also exhibits a long concave band in the temperature range 1075-1100℃，which may be related to the solutionizing of M3B2 phase. At temperatures lower than 1000℃ and strain rates higher than 0.1s-1, the material may be subjected to potential instabilities, while at temperatures higher than 1050℃ and strain rates lower than 0.01s-1 , the material exhibits significant grain coarsening, furthermore, the wedge cracking would appear at 1200℃ and 0.001s-1. On the basis of the constitutive behavior of GH2674 alloy as revealed in the processing map, the hot working schedules have been designed primarily