通过高周疲劳试验研究了裂纹源位置对6005A-T6铝合金挤压型材高周疲劳寿命的影响。结果表明：6005A-T6铝合金挤压型材在应力比0.1下的中值疲劳强度为164.5 MPa，疲劳强度较高，但疲劳寿命分布较分散；在最大应力200 MPa条件下，具有不同疲劳寿命试样的疲劳裂纹源区的面积较小，疲劳裂纹扩展区均由疲劳条带和二次裂纹组成，瞬断区的面积较大，均由孔洞和韧窝组成；在相同最大应力下疲劳寿命存在差异的原因在于疲劳裂纹源位置的不同，在最大应力为200 MPa条件下，疲劳裂纹源位于孔洞缺陷处试样的疲劳寿命最长，比疲劳裂纹源位于氧化夹杂物处试样的疲劳寿命延长一个数量级，疲劳裂纹源位于Al₇（CrFe）第二相颗粒处试样的疲劳寿命居于二者之间。

The effect of crack source location on high cycle fatigue life of 6005A-T6 aluminum alloy extruded profiles was studied by high cycle fatigue tests. The results show that the median fatigue strength of 6005A-T6 aluminum alloy extruded profiles was 164.5 MPa at the stress ratio of 0.1; the fatigue strength was relatively high, but the fatigue life distribution was relatively dispersal. Under the maximum stress of 200 MPa, the fatigue crack source region of samples with different fatigue lives was small; the fatigue crack propagation region consisted of fatigue strips and secondary cracks; the area of transient fracture region was large, and the region consisted of holes and dimples. The main reason for the difference in fatigue life under the same maximum stress was the difference location of fatigue crack source. Under the maximum stress of 200 MPa, the fatigue life of the sample with fatigue crack source in holes was the longest, which was one order of magnitude larger than that with fatigue crack source on oxide inclusions, and the fatigue life of the sample with the fatigue crack source in Al₇(CrFe) second phase particles was between the two.