6061-T6铝合金阶段性疲劳损伤试验研究

RESEARCH ON STAGED FATIGUE DAMAGE OF ALUMINUM ALLOY 6061-T6

开展车用铝合金疲劳损伤检测与评估,对汽车轻量化材料的应用具有重要的理论意义和工程价值。基于CT损伤检测和缺陷重构技术,开展了6061-T6铝合金阶段性疲劳损伤特性研究。首先,对车用铝合金材料进行静拉伸试验和阶段性疲劳循环加载试验,得到了不同阶段的疲劳损伤试样。接着,利用基于X-ray的CT损伤检测,实现损伤试样内部的孔洞和裂纹等缺陷信息的获取,在AVIZO可视化软件中进行了缺陷特征的三维重构,研究了不同阶段试样损伤缺陷连续性特征。最后,根据不同阶段的疲劳损伤试样的损伤程度,分析了准确表征损伤程度的相关损伤演化参量的变化特性,包括孔隙率、损伤体积分数等。综合各损伤表征参量随循环次数的变化分析,损伤体积分数作为损伤参量不仅决定损伤占比的多少,对损伤尺寸也存在直接影响,更能反映损伤的连续性变化,从而能够进行合理有效的缺陷演化过程分析。

It is of great theoretical significance and engineering value to carry out fatigue damage detection and evaluation of aluminum alloy for application of automobile lightweight materials.In this paper,the periodic fatigue damage characteristics of 6061-T6 aluminum alloy were studied based on CT damage detection and defect reconstruction technology.Firstly,fatigue damage samples of 6061-T6 aluminum alloy at different stages are obtained by static tensile test and periodic fatigue test.Secondly,defect information of holes and cracks in the damaged samples are achieved through X-ray CT scanning,and 3D reconstruction of defect features is carried out by AVIZO visualization software,and continuity features of the damage defects in different stages are studied.Finally,the change characteristics of damage evolution parameters,including porosity,damage volume fraction,are analyzed according to damage degree of fatigue damage samples in different stages.Based on the analysis of change of damage characterization parameters with the number of cycles,the damage volume fraction,as a damage parameter,determines the proportion of damage,and has a direct impact on the size of damage,which can better reflect the continuous change of damage,so as to conduct a reasonable and effective analysis of defect evolution process.