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以TC4合金等温锻造为例,提出一种基于多塑性变形机制耦合的数值模拟方法。通过对等温锻造过程中塑性变形机制的研究和对应变速率敏感指数以及TC4合金动态再结晶的分析,建立材料常规塑性变形、超塑性变形和蠕变变形的判据。并依据多塑性变形机制判据来确定坯料内部各单元的实时塑性变形机制,同时采用相应的本构方程,使模拟结果更符合实际情况,从而能真实反映航空难变形材料的等温锻造工艺过程:普通塑性变形、超塑性变形和等温保压充填模具过程等。模拟结果表明,变形材料并非处于单一塑性变形机制,而是多种变形机制相互协调,并且随着变形的进行,材料各单元的变形机制也随之改变。等温锻造过程中,上述机制的改变与材料的动态再结晶密切相关。
Taking isothermal forging of TC4 as an example, a numerical simulation method based on the coupling mechanism of multi-plastic deformation was proposed. Based on the research of plastic deformation mechanism in isothermal forging process and the analysis of strain rate sensitivity index and dynamic recrystallization of TC4 alloy, the criterion of conventional plastic deformation, superplastic deformation and creep deformation was established. And based on the criterion of multi-plastic deformation mechanism, the real-time plastic deformation mechanism of each unit in the blank is determined. At the same time, the corresponding constitutive equation is adopted to make the simulation result more in line with the actual situation, which can truly reflect the isothermal forging process of air- Ordinary plastic deformation, superplastic deformation and isothermal packing mold filling process. The simulation results show that the deformation material is not in a single plastic deformation mechanism, but a variety of deformation mechanisms are coordinated with each other, and with the deformation, the deformation mechanism of the material units also will change. In isothermal forging process, the above mechanism is closely related to the dynamic recrystallization of the material.