摘要
以热模拟压缩试验的应力-应变数据为基础，根据DMM模型（dynamic materials model，动态材料模型）建立固溶态粗晶GH4169合金的热加工图；结合光学显微镜（OM）及电子背散射衍射（EBSD）分析，确定合金压缩变形的稳定区和失稳区，研究不同变形条件下的微观变形机制，并提出工艺参数范围。结果表明，粗晶GH4169合金在应变速率为10^-0．25～1S^-1、变形温度为950～1100℃的条件下发生热加工流变失稳，失稳原因主要与局部塑性流动引发的裂纹有关；粗晶GH4169合金在中、低应变速率区有3个典型的动态再结晶区域，在应变速率为10^-3S^-1、变形温度为950℃时局部能量耗散效率（η）的极大值主要与晶界析出δ相对动态再结晶的促进作用以及局部的晶内形核有关；综合考虑能量耗散效率、伸长率和组织状态，建议粗晶GH4169合金的始锻和终锻分别在应变速率为10^-2.7～10^-1.5S^-1、变形温度为1087．5～1100℃和应变速率为10^-2.5～10^-1.5S^-1、变形温度为1000～1065℃的条件下进行。
Based on the stress-strain data of thermal simulation compression tests, the processing maps of the annealed GH4169 alloy with coarse grains were established according to the dynamic materials model （DMM）. Combined with the optical microscopy （OM） observations and the electron backscatter diffraction （EBSD） technique analysis, the stable and instable regions of the annealed GH4169 alloy with coarse grains were determined and the mechanisms of deformation under different conditions were investigated. The suggested processing parameters of the annealed GH4169 alloy with coarse grains were also studied. The results show that the flow instability of the annealed alloy with coarse grains occurring at the strain rates of 10^-0.25～1 s^-1 and the temperatures of 950～1 100℃ is mainly related to the cracking induced by the local plastic flow. Three classic zones of dynamic recrystallization for GH4169 alloy with coarse grains are found in the region with moderate and low strain rates. The maxium energy dissipation efficiency occurring at the strain rate of lO^-3s^-1 and the temperature of 950 ℃ is closely associated with the promotion of dynamic recrystallization due to the δ phases precipated along the grain boundaries as well as the local nucleation of dynamic recrystallization inside the grain.Comprehensively considering the energy dissipation efficiency,elongation and microstructure,the process parameters of the starting forging for the alloy with coarse grains are suggested to be the strain rates of 10^-2.7～10^-1.5s^-1 and temperatures of 1087.5～1100℃,and those of the final forging are suggested to be the strain rates of 10^-2.5～10^-1.5s^-1 and temperatures of 1000～1065℃.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2012年第3期281-290,共10页
Materials Science and Engineering of Powder Metallurgy
基金
湖南省自然科学基金资助项目(11JJ3064)
中南大学中央高校基本科研业务费专项(2011QNZT048)
湖南省博士后科研资助专项计划(2011RS4074)
关键词
时伟
王岩
邵文柱
甄良
刘文胜
GH4169 alloy
processing map
instability
dynamic recrystallization
