6063T4铝合金脉冲电流辅助拉伸力学性能实验研究

Experimental study on the mechanical properties of 6063T4 aluminum alloy under electropulsing-assisted tensile

为研究电流密度对材料力学性能的影响,对6063T4铝合金板材进行了脉冲电流辅助单向拉伸试验.理论分析了拉伸过程中电能转化温升的效率,探讨了脉冲电流辅助拉伸过程中材料的动态应变时效(DSA)现象及其机理,定量分析了电流密度与应力降之间的关系,并观察了试验前后试样的微观组织及断口形貌.结果表明,脉冲电流降低了材料流动应力,提高了材料塑性;电能转化为温升的效率约为60%;随着电流密度或脉冲数的增加,DSA现象越发显著;在给定的电流密度下,应力降值随着变形量的增加呈线性增加;光学微观组织表明,材料在相对较低的温度(165℃)下发生了动态再结晶;断口形貌分析显示电流辅助单向拉伸所获得的断口中韧窝数量以及撕裂棱增多,材料塑性提高.

The electropulsing-assisted tensile （EAT） of 6063T4 aluminum alloy sheet was carried out to investigate the influence of electropulsing on the mechanical properties of the material. Moreover, the efficiency of electric energy conversion to temperature rise during EAT was theoretically analyzed, and the dynamic strain aging （DSA） phenomenon occurred in EAT and its mechanisms were discussed. The relationship of electropulsing and stress drop was studied quantitatively, and the microstructure near the fracture zone and fracture morphology was observed by means of microanalysis. The results indicated that the electropulsing reduced the flow stress during uniaxial tensile test and improved the plasticity of the material and the electric energy conversion was around 60%. Higher the electric electropulsing promoted the DSA phenomenon more obvious. Under stress drop increased linearly with the increase of deformation current density or more the number of the given electric current density, the Optical microstructures showed that recrystallization was occurred on the specimen after EAT at relatively low temperature （ 165 ℃ ） , and the fracture morphology analysis indicated that the number of dimples and the tearing edges increased in the fracture surface obtained by EAT, resulting in the improvement of plasticity of the material.