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变形温度为480℃时,对1420铝锂合金进行了不同应变速率、脉冲电流密度和脉冲频率的电致超塑性拉伸试验;通过对现有超塑性本构方程进行修正,建立了耦合脉冲电流密度和脉冲频率的超塑性本构方程,并对其进行了试验验证。研究结果表明:变形温度为480℃、应变速率为0.001 s-1时,在1420铝锂合金的超塑性拉伸试验中施加脉冲电流后,材料的流动应力比未施加电流时有所降低,伸长率有所增加;当脉冲电流密度为192 A·mm-2、脉冲频率为150 Hz时,材料的流动应力最小,伸长率最大。通过耦合脉冲电流参数的本构方程计算的流动应力值与试验数据吻合较好,能够准确预测1420铝锂合金在电致超塑性变形中流动应力的变化趋势。
At deformation temperature of 480 ℃, the superplastic tensile tests of 1420 Al-Li alloy under different strain rates, pulse current densities and pulse frequencies were carried out. By modifying the existing superplastic constitutive equation, the coupling pulse current Density and pulse frequency of the superplastic constitutive equation, and its experimental verification. The results show that when the deformation temperature is 480 ℃ and the strain rate is 0.001 s-1, the flow stress of the 1420 Al-Li alloy in the superplastic tensile test is lower than that without the current applied. When the pulse current density is 192 A · mm-2 and the pulse frequency is 150 Hz, the material has the lowest flow stress and the highest elongation. The flow stress calculated by the constitutive equation of the coupled pulse current parameters is in good agreement with the experimental data and can accurately predict the trend of the flow stress in 1420 Al-Li alloy under the superplastic deformation.