1420铝锂合金电致超塑性本构方程  

Constitutive equation of electro-superplastic for 1420 Al- Li alloy

作　　者：张宁[1] 张艳苓[1] 毕静[1] 侯红亮[1] 

机构地区：[1]北京航空制造工程研究所,北京100024

出　　处：《锻压技术》2015年第5期63-68,共6页Forging & Stamping Technology

基　　金：国家自然科学基金资助项目(51334006;51405457);国家重点基础研究发展计划资助项目(2011CB012803)

摘　　要：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。The uniaxial tensile tests of electro-superplastic for 1420 Al -Li alloy were carried out with different parameters of strain rate, pulse current density and pulse frequency at the deformation temperature of 480 ℃. Through revising the current constitutive equations of superplastic, the constitutive equation of electro-superplastic for 1420 Al - Li alloy coupling with pulse current density and pulse frequency was established, and then the constitutive equation was validated by experimental data. The results show that, when the deformation tem- perature is 480 ℃ and the strain rate is 0. 001 s -1, the flow stress of alloy with uniaxial superplastic tensile tests of being added pulse cur- rent density is slightly lower than that without being added pulse current density, and the elongation of alloy increases a little. Meanwhile, when pulse current density is 192 A· mm-2and the pulse frequency is 150 Hz, the minimum flow stress and the maximum elongation of alloy are obtained. And the flow stress calculated by the constitutive equation coupling with pulse current parameters is close to the experimental data, and the change trend of flow stress during electro-superplastic forming for 1420 Al - Li alloy can be predicted accurately.

关 键 词：1420铝锂合金 电致超塑性 本构方程 脉冲电流 

分 类 号：TG146.21[一般工业技术—材料科学与工程]