This study aims to investigate the influence of shot penning on fatigue crack growth rate of chemical milling product Al 2524-T3 which have been stretched. This alloys were stretched beyond yield stress, namely 1%, 3% and 5% of each, and then performed chemical milling process of one side. The etching used in chemical milling process were NaOH+Na₂S+H₂O solutions with certain concentration. The surface was performed shot penning process with varying intensity of 0.03 A, 0.05 A and 0.07 A, respectively. These material were then tested its crack growth rate. The crack growth rate tests were performed under 20% stress level, stress ratio of 0.3 and at frequency 7-13 Hz. The average of crack propagation data against the cycle number were processed using an incremental method, in accordance with ASTM E647 standard, to obtain crack growth rate curve (da/dN vs. ΔK). The results show that the increase of shot penning intensity has no significant effect on the fatigue life, with the growth average of 4,5%. The highest increase occurred at the shot intensity of 0.03 A, 0.2 times its chemical milling, while the lowest decrease occurred at the shot intensity of 0.07A, 0.012 times its chemical milling. The crack retardation effect at the beginning of the crack plays a role in reducing the crack propagation rate.

本研究旨在研究喷丸处理对拉伸后化学铣削产品Al 2524-T3疲劳裂纹扩展速率的影响。将该合金拉伸至超过屈服应力，即分别为1％，3％和5％，然后进行一侧的化学铣削加工。化学研磨过程中使用的蚀刻是NaOH + Na ₂ S + H ₂O溶液有一定浓度。表面进行喷丸处理，强度分别为0.03 A，0.05 A和0.07A。然后测试这些材料的裂纹扩展速率。裂纹扩展速率测试是在20％应力水平，0.3应力比和7-13 Hz频率下进行的。根据ASTM E647标准，使用增量方法处理裂纹扩展数据相对于循环次数的平均值，以获得裂纹扩展速率曲线（da / dN与ΔK）。结果表明，喷丸强度的提高对疲劳寿命无明显影响，平均增长率为4.5％。增幅最大的是0.03 A的冲击强度，是化学研磨的0.2倍，降幅最小的是0.07A的强度，化学冲击的0.012倍。