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针对SiCp/Al材料塑性低、容易产生裂纹的缺陷,研究了高密度脉冲电流对SiCp/Al板材裂纹的修复作用。采用室温拉伸方法预制裂纹,在扫描电子显微镜(SEM)下标定裂纹后,对试样进行脉冲电流(电流密度为31.25A/mm~2)处理,对比分析脉冲电流处理前后裂纹形貌,测试电流处理对含裂纹试样力学性能的影响。结果显示,脉冲电流处理后,试样表面尺寸较小的裂纹直接被焊合,尺寸较大的裂纹宽度减小并且尖端出现了熔化现象;对比试样脉冲电流处理前后的延伸率发现,脉冲电流处理可以使试样预变形后的延伸率提高38%。采用电-热-力耦合的数值分析方法求得通电后SiCp/Al板材裂纹附近的电流场、温度场和应力场,并进行了脉冲电流处理对裂纹修复的机理分析,为脉冲电流修复技术的应用奠定理论基础。
Aiming at the defects of low plasticity and easy crack generation of SiCp / Al, the repairing effect of high density pulse current on the crack of SiCp / Al sheet was studied. The cracks were pre-formed at room temperature by tensile test. The specimens were subjected to pulsed current (current density 31.25 A / mm 2) after the crack was cracked under a scanning electron microscope (SEM). The crack morphology before and after the pulse current treatment was analyzed. Effect of Current Treatment on Mechanical Properties of Cracked Specimens. The results show that after the pulse current treatment, the cracks on the surface of the sample are welded directly, the crack width of the larger size decreases and the melting phenomenon occurs at the tip. The elongation of the sample before and after the pulse current treatment shows that the pulse current The treatment can increase the elongation of the sample after pre-deformation by 38%. The current field, temperature field and stress field near the cracks of SiCp / Al sheet after electrification were obtained by the numerical analysis method of electric-thermal-mechanical coupling. The mechanism of crack repair by pulse current treatment was analyzed. Application laid the theoretical foundation.