基于微观组织演变的钛合金本构关系模型及应用

【作者】 陈胜晖；

【导师】 李淼泉；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2004， 硕士

【摘要】 钛合金是航空工业中应用广泛的金属结构材料。由于钛合金的组织和性能对变形时的热加工参数比较敏感，使其适合的热加工参数范围较狭隘，用一般的锻造方法难以获得理想的微观组织和性能。研究钛合金在锻造成形过程中的变形规律，对获得理想的锻件性能有重要作用。 建立金属材料的本构关系模型，是运用有限元方法对金属塑性成形过程进行数值模拟的前提条件。在金属材料的热成形中，除了经历应力和应变的变化外，材料的微观组织也经历一系列复杂的变化。本文在TC6合金微观组织实验的基础上，研究了锻造工艺参数对微观组织的影响，提出了基于微观组织演变的本构关系模型，并运用遗传算法求解材料常数。 本文基于微观组织演变的本构关系模型，对不同变形温度、凸模速度和摩擦条件下钛合金盘的等温锻造过程进行了三维数值模拟，研究了变形工艺参数对等效应变、等效应力和晶粒尺寸的影响，计算了各变形条件下的位移—载荷曲线。更多还原

【Abstract】 Titanium alloy is a structure material of metal widely used in aircraft industry. The microstructure and performance of titanium is relatively sensitive to the process parameters in the hot deformation processes, and the optimal process parameters is in relatively narrow range, and then it is in difficulty to obtain ideal microstructure and performance with the common forging technique. To study the deformation mechanism in forging process of titanium alloy plays an important role in practice.To establish the constitutive relationship is a precondition to simulate the plastic deformation during the hot plastic deformation of metals. Besides the stress and strain change of metals, microstructure undergoes a series of complicated changes. Based on the experimental results of microstructure of a TC6 alloy, influence of process parameters on microstructure evolution has been studied, the constitutive relationship based on microstructure evolution has been developed, and the material constants have been calculated with the help of evolution programming.Based on the constitutive relationship coupled microstructure evolution, 3D-FE simulation of isothermal forging process of TC6 titanium alloy disc is performed dealing with different deformation temperature, punch velocity and shear factor of friction, effect of process parameters on equivalent strain, equivalent stress and grain size is calculated, and load-displacement curve is calculated.更多还原