研究目的
Investigating the effects of laser peening on the fatigue strength and defect tolerance of the 7075-T651 aluminum alloy.
研究成果
LP induced a deeper compressive residual stress compared to SP, significantly improving the fatigue strength and defect tolerance of the aluminum alloy. The maximum defect size rendered harmless by LP was 0.4 mm, larger than that by SP (0.1 mm). The apparent threshold stress intensity factor range increased significantly with LP, demonstrating its effectiveness in enhancing the material's resistance to fatigue crack growth.
研究不足
The study focused on the 7075-T651 aluminum alloy and specific peening conditions. The effects of surface roughness and the applicability of the findings to other materials or peening conditions were not extensively explored.
1：Experimental Design and Method Selection:
The study involved bending fatigue tests on aluminum alloy specimens treated with laser peening (LP) and shot peening (SP), including specimens with artificial semicircular slits to emulate surface defects.
2：Sample Selection and Data Sources:
High-strength aluminum alloy A7075-T651 was used, with specimens classified into six groups based on treatment and defect presence.
3：List of Experimental Equipment and Materials:
A Q-switched Nd:YAG laser for LP, ZrO2 ceramic shots for SP, and a bending fatigue testing machine for fatigue tests.
4：Experimental Procedures and Operational Workflow:
LP and SP treatments were applied to specimens, followed by the introduction of semicircular slits in some specimens. Fatigue tests were conducted at a stress ratio R = 0 and a frequency of 20 Hz.
5：Data Analysis Methods:
The effects of LP and SP on fatigue strength and defect tolerance were analyzed using fracture mechanics, including the calculation of apparent threshold stress intensity factor ranges and the construction of Kitagawa-Takahashi diagrams.
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