镍基高温合金热塑性变形晶粒细化与粗化的博弈关系及演进

Game Relation Between Grain Refinement and Grain Coarsening in Thermoplastic Deformation of Nickel-based Superalloy and Its Evolution

为深入揭示Ni80A镍基高温合金热塑性变形过程中晶粒细化与晶粒粗化之间的博弈关系及演进,基于晶粒细化等温变形实验和晶粒生长粗化实验分别建立了动态再结晶和晶粒生长数学模型。结合所建数学模型和有限元分析发现,Ni80A镍基高温合金在热塑性变形过程中动态再结晶晶粒细化和晶粒生长粗化的博弈关系及演进共同决定了晶粒尺寸的非线性演变。本工作绘制了两种晶粒尺寸演变机制的博弈关系图并分析其对晶粒尺寸的单独及耦合作用。结果表明:变形初期晶粒生长粗化占主导地位,变形中后期动态再结晶晶粒细化占主导地位,整个热塑性变形过程中二者相互博弈,共同影响试样的晶粒尺寸。

In order to reveal the game relation and evolution between grain refinement and grain coarsening in the process of Ni80A thermoplastic deformation,dynamic recrystallization and grain growth models were established based on grain refinement isothermal deformation experiment and grain growth coarsening experiment,respectively.Based on the mathematical model and finite element analysis,it was found that the game relation of dynamic recrystallization grain refinement and grain growth coarsening in the process of Ni80A thermoplastic deformation jointly determine the nonlinear evolution of grain size,and the game relation diagram of the two mechanisms of grain size evolution was drawn to analyze their independent and coupling effects on grain size.The results show that the grain growth coarsening is dominant in the early stage of deformation,the dynamic recrystallization grain refinement is dominant in the middle and late stage of deformation,and the grain size is affected by the game of them in the whole thermoplastic deformation process.