中文摘要：

针对所构建的GH738高温合金热变形过程动态再结晶、亚动态（静态）再结晶和晶粒长大的晶粒组织演化模型,利用FORTRAN语言将锻造变形过程中所有模型写入有限元软件MSC.SUPERFORM的用户子程序中,对软件进行二次开发并对该高温合金晶粒组织演化进行数值模拟.通过对Gleeble热压缩试样及直径250 mm涡轮盘实际锻造结果与数值模拟进行对比分析,证实了GH738高温合金显微组织演化模型的正确性和该软件二次开发的可行性.对直径1250 mm超大型涡轮盘生产进行模拟预测,模拟结果显示适宜的热加工条件为变形温度1040—1100℃,锻造速度10-25 mm/s;同时与实际在变形温度1080℃,变形速度10 mm/s条件下锻造的直径1250 mm超大型涡轮盘组织进行比较,发现该模拟结果与实际结果吻合性较好,基本达到了组织的精确预测控制.此外,结合以上锻造及模拟经验,对国内GH738高温合金直径1400 mm特大型涡轮盘进行了锻造组织预测.

英文摘要：

Microstructure evolution models of dynamic recrystallization.met a -dynamic recrystallization, static recrystallization and grain growth behavior for GH738 superallov were implanted into finite element software MSC.SUPERFORM with FORTRAN language by means of the user subroutines, in order to add the function of predicting microstructure evolution during hot forging to MSC. SUPERFORM.Microstructure evolution models of GH738 superalloy and the feasibility of the redeveloped MSC.SUPERFORM were verified by comparison between the simulated and experimental results on hot compression specimens and a turbine disc 250 mm in diameter.The numerical simulation of the forging turbine disc 1250 mm in diameter was carried out by the redeveloped MSC.SUPERFORM, showing that hot working window was in temperature range of 1040—1100℃.strain rate range of 10—25 mm/s.Comparison between simulated and actual forging results in the condition of 1080℃, 10 mm/s showed that the simulated microstructure was in good agreement with the actual result. Besides,the numerical simulation of the forging turbine disk 1400 mm in diameter was also carried out using redeveloped MSC.SUPERFORM.Therefore,the construction of microstructure evolution models of GH738 superalloy and the feasibility of the redeveloped MSC.SUPERFORM are of great significance to accurate control and prediction of turbine disc microstructure.