钛合金宽弦空心风扇叶片高温弯扭成形及性能调控研究

Research on Twist-Bend Forming and Performance Control of Titanium Alloy Wide-Chord Hollow Fan Blade Under High Temperature

利用UTM 5504X电子万能试验机对TC4钛合金在变形温度650~850℃和应变速率10^(-3)–1 s^(-1)条件下进行高温拉伸试验,研究了TC4钛合金热变形行为,建立了修正的Misiolek硬化方程,可以准确预测该材料在不同变形条件下的流动应力。同时构建TC4钛合金空心叶片的高温弯扭成形有限元模型,结合有限元仿真研究结果确定空心风扇叶片弯扭成形的最佳工艺参数为扭转成形温度750℃、扭转成形截面550 mm和扭转角速度1.938°/min。结合微观组织试验观察发现,高温变形条件下α相含量减少,β相含量持续升高,材料具备较高的延伸率和塑性成形性能。最终通过弯扭成形制备的空心叶片的叶身整体过渡圆滑、无表面缺陷,成形质量良好,研究结果可为TC4钛合金宽弦空心风扇叶片批量化制造生产提供指导性意见。

The thermal deformation behavior of TC4 titanium alloy was studied by using UTM 5504X electronic universal testing machine at 650–850℃and strain rate 10^(-3)–1 s^(-1).The modified Misiolek hardening model was established and the flow stress of the material under different deformation conditions can be predicted accurately by this model.At the same time,the finite element model of high temperature twist-bend forming of TC4 titanium alloy hollow blade was established.Considering the simulation results,the optimal process parameters of twist-bend forming of TC4 titanium alloy hollow blade were determined as follows:twist forming temperature 750℃,twist forming section 550 mm and twist angular velocity 1.938°/min.The result is found that the content ofαphase decreases and the content ofβphase continues to increase under the condition of high temperature deformation,and the material has high elongation and plastic forming property.Finally,the hollow blade prepared by bending and torsional forming has a smooth overall transition,no surface defects and has good forming quality.The research results can provide guidance for the mass manufacturing of TC4 titanium alloy wide-string hollow fan blade.