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随着航空工业的迅速发展,大飞机和新一代军机的研制,钛合金大型筋板件的应用日益广泛,等温局部加载技术为该类构件的成形提供了新的途径。然而,等温局部加载成形是一个多因素耦合作用下的复杂成形过程,工艺参数控制不当将产生粗晶、组织不均匀等缺陷。为此,文章采用内变量法,建立了TA15合金高温变形微观组织演化物理模型,并与有限元软件DEFORM 3D结合对TA15合金筋板件等温局部加载成形过程等轴α相晶粒尺寸演化进行数值模拟。结果表明,锻件先加载区、后加载区及变形过渡区晶粒尺寸基本一致;随着温度的升高,锻件等轴α相晶粒尺寸平均值,呈先减小,后增加的趋势;锻件等轴α相平均晶粒尺寸随模具运动速度增加,先快速减小,后趋于平缓,较大的模具运动速度易造成组织不均匀性增加;采用只局部加载的加载方式,可以获得比采用先局部后整体的加载方式,更均匀细小的组织。
With the rapid development of the aviation industry, the development of large aircraft and a new generation of military aircraft, the application of titanium alloy large rib plate is increasingly widespread, isothermal loading technology provides a new way for the formation of such components. However, the isothermal partial load forming is a complex forming process under the action of multiple factors. Improper control of the process parameters will result in defects such as coarse grains and uneven microstructure. Therefore, the article uses the internal variable method to establish the physical model of high-temperature deformation microstructure evolution of TA15 alloy and combines with the finite element software DEFORM 3D to carry out numerical simulation of the isometric α-phase grain size evolution during the isothermal local loading process of TA15 alloy rebars simulation. The results show that the grain sizes of the forging first loading zone, the post loading zone and the deformation transition zone are basically the same. With the increase of the temperature, the average α-phase grain size of the forging decreases first and then increases. Forging The average grain size of the equiaxed α phase increases rapidly with the mold moving speed, then decreases rapidly and then tends to be gentle. Larger mold moving speed can easily lead to the increase of the nonuniformity of the tissue. By using the method of partial loading only, After the first part of the overall loading, more uniform organization.