7075铝合金以其独特的性能广泛应用于载运工具各个行业中,但是,铝合金在焊接后会出现疲劳强度降低的现象,这对载运工具的安全性产能生了消极影响.针对这一现象,采用局部激光表面处理法来改善7075铝合金的疲劳性能.对未处理试样和局部激光表面处理后试样的疲劳裂纹扩展速率的研究表明,局部激光表面处理能有效降低疲劳裂纹扩展速率,提高疲劳寿命.ANSYS有限元残余应力分析及硬度试验表明,局部激光表面处理后试样上形成的残余应力场和局部软化现象是疲劳裂纹扩展速率降低的主要因素.%7075 aluminum alloy is widely used in the industries of vehicles for its unique performance, but it has a poor fatigue properties after welding, which may produce a negative effect to the safety of vehicles. Thus, a method to improve the fatigue property for 7075 aluminum alloy by local laser surface treatment (LLST) is studied in this paper. Based on experimental results of the fatigue crack growth rate ( FCGR) for the laser treated specimens and untreated specimens, it is shown that LLST can result in significant reduction of FCGR, and thus improve the fatigue life. The residual stress analysis based on ANSYS procedure and hardness test show that the residual stress and partly softening phenomenon are the main reason for the reduction of FCGR.
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