Local laser heating treatment using a defocussed laser beam was applied to the surface of 2‐mm‐thick AA2024‐T3 sheets. Two different treatment designs—namely, lines and circles—as well as the positioning and number of treatments were investigated regarding their potential to retard the propagation of through‐thickness fatigue cracks. The highest fatigue crack growth life extension of 285% was achieved by the application of four laser heating lines or two circles on each specimen side. The induced compressive residual stress field through the LH process is primarily responsible for an improvement in fatigue crack growth life. An emphasis was placed on investigating the effect of the treatment on the possible reduction of tensile and fatigue strength (S‐N life). If only one line was applied transverse to the loading direction or only one circle was used, the reduction of fatigue strength was comparable to the reduction of fatigue strength resulting from the stress concentration introduced due to the presence of a rivet hole.

中文翻译：

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激光加热对AA2024力学性能，残余应力和疲劳裂纹扩展的影响

在2毫米厚的AA2024-T3纸的表面上进行了使用散焦激光束的局部激光加热处理。研究了两种不同的处理设计（即线和圆），以及处理的位置和次数，以了解它们可能会阻止全厚度疲劳裂纹扩展的可能性。通过在每个试样侧面施加四个激光加热线或两个圆，可以实现最高的疲劳裂纹扩展寿命285％的延长。通过LH过程引起的压缩残余应力场主要负责延长疲劳裂纹的生长寿命。重点放在研究处理对可能降低抗拉强度和疲劳强度（SN寿命）的影响上。