电缆用Al-Fe系铝合金导体材料的恒应力高温压缩蠕变行为

High Temperature Compressive Creep Behavior of Al-Fe Series Aluminum Alloy Conductor Material for Cable

对电缆用Al-Fe系铝合金导体材料进行恒应力(63.6,72.6,78.3,84.7 MPa)高温(90℃)压缩蠕变试验,研究了压缩应力σ对稳态蠕变速率ε·的影响,建立了压缩蠕变本构方程,分析了压缩蠕变机制。结果表明:铝合金试样的稳态蠕变速率随着压缩应力的增加成倍增大;90℃下铝合金试样的蠕变本构方程为ε·=σ^(9.27)e^(-52.2),拟合曲线和试验结果的相关系数达0.9976;铝合金蠕变过程中存在门槛应力,其值为34.2 MPa,引入门槛应力对蠕变方程进行修正,修正方程计算所得稳态蠕变速率与试验值的相对误差为8%,证明模型准确,得到的真应力指数为5,说明电缆用Al-Fe系铝合金导体材料在90℃下的压缩蠕变行为是由位错攀移机制主导的第二相粒子强化类蠕变。

Compressive creep tests at constant stress(63.6,72.6,78.3,84.7 MPa)at high temperature(90℃)were carried out on Al-Fe series aluminum alloy conductor material for cable.The effect of the compression stressσon the steady state creep rateε·was studied.The compressive creep constitutive equation was established,and the mechanism of the compressive creep was analyzed.The results show that the steady state creep rate of aluminum alloy samples increased exponentially with the increase of compressive stress.The creep constitutive equation of the aluminum alloy sample at 90℃wasε·=σ^(9.27)e^(-52.2),the correlation coefficient between the fitting curve and the test result reached 0.9976.There was threshold stress during creep process of alumium alloy,which was 34.2 MPa.The threshold stress was introduced to modify the creep equation.The relative error between the calculated steady state creep rate by the modified equation and the test value was 8%,which proved that the model was accurate.The true stress exponent was 5,indicating the compressive creep behavior of Al-Fe series aluminum alloy material for cable at 90℃was the second phase particle strengthened creep-like behavior dominated by dislocation climbing mechanism.