【作者】 党淼；

【导师】 齐广霞；

【作者基本信息】 沈阳理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 在航空发动机中,叶片起着能量转换的关键作用。近年来,对叶片成形过程的研究,已从宏观塑性流动行为转向内部微观组织模拟、力学性能预测与质量控制等方面。金属内部的微观组织演变在很大程度上决定了叶片的宏观力学性能。因此,了解材料的微观组织演变及其影响因素对控制产品的力学性能是非常重要的。而现有的有限元模拟软件不具备模拟微观组织演变的功能,因此,有必要将微观组织模型加入有限元模拟软件DEFORM-3D的用户子程序中,以实现金属在热锻过程中的微观组织演变数值模拟研究。本文完成的主要工作如下:(1)以TA11合金为研究对象,通过热模拟压缩实验,获得了TA11合金在热变形过程中的应力应变曲线,并对其高温流变行为进行了分析。基于高温流变行为建立了TA11合金的塑性变形本构方程。模型的计算值与实验值的平均误差小于13.9%,能较好的描述TA11钛合金在高温变形时的流动行为。(2)通过金相实验研究了变形工艺参数对微观组织的影响,基于微观组织演变规律建立了(α+β)两相区塑性变形过程中动态再结晶体积分数和动态再结晶晶粒尺寸模型,并建立了初生α相平均晶粒尺寸模型。模型的计算值与实测值的平均误差小于14.9%,可以较好的描述TA11合金在高温变形过程中的微观组织演变行为。(3)将TA11合金的微观组织模型添加至DEFORM-3D的用户子程序中,使其具备了对TA11合金热成形过程中微观组织的预测及模拟功能,并通过对圆柱体镦粗的模拟验证了程序的可靠性。(4)对TA11合金叶片的精锻过程进行了微观组织模拟,分析了变形速度、变形温度和压下量对叶片微观组织演变的影响,获得了叶片在制坯、预锻和终锻过程中的工艺参数的优化和微观组织演变的分布规律。研究结果对叶片精锻过程工艺参数的制定具有重要的指导意义。更多还原

【Abstract】 Blade plays a key role in energy conversion in aero-engine. In recent years, the studies of blade forming process have turned from the macro-plastic flow behavior to the microstructure simulation, mechanical property prediction, quality control and so on. The microstructure evolution of the metallic material determines the macro-mechanical properties of the blade to a large extent. Therefore, it is extremely important to control the mechanical properties of the product by understanding the microstructure evolution and its influencing factors of materials. The existing finite element simulation software does not have the function to simulate microstructure evolution. Therefore, it is necessary to embed the microstructure evolution model in user subroutines of DEFORM-3D software in order to simulation the microstructure evolution during hot forging process. The research works are summarized as follows.(1) Through the thermal simulation compression test of TA11 alloy, the stress-strain curves during the hot deformation have been obtained. And the flow behavior of high temperature has also analyzed. Based on flow behavior of high temperature, the constitutive equations of plastic deformation for TA11 alloy is established. The average error between the equation and experimental data of the model is smaller than 13.9%. The model can be used to describe the flow behavior of TA11 titanium alloy during the thermal processing.(2) Through the metallurgical technique, the effects of the deformation process parameters on the microstructure have been studied. The models of volume fraction of dynamic recrystallization and grain size of dynamic recrystallization during dual phase (α+β) plastic deformation process have been established based on microstructure evolution. Average grain size model of primaryαphase of TA11 titanium alloy is established. The average error between the equation and experimental data of the model is smaller than 14.9%. The model can be used to describe the law of microstructure evolution of TA11 titanium alloy during the thermal processing.(3) In order to have the function to predict and simulate microstructure during hot forging process of TA11 alloy, the microstructure evolution model have been embedded in user subroutines of DEFORM-3D software. And the reliability of the program is verified through the simulation of cylinder upsetting.(4) The microstructure simulation of TA11 precision forging process is carried out. The influences of the deformation speed, deformation temperature and height reduction on microstructure evolution are analyzed. The distributing rule of the microstructure evolution and optimization of parameters have been obtained during cogging, pre-forging and finish forging processes of the blade. The results are of great significance to select the technology parameters of the precision forging process of the blade.更多还原