AZ31B镁合金激光冲击强化及抗应力腐蚀研究

Research on Laser Shock Strengthening and Stress Corrosion Cracking Resistance of AZ31B Magnesium Alloy

为了研究激光冲击强化对镁合金性能的影响,根据优化后的工艺参数,采用钕玻璃脉冲激光,对轧制态AZ31B镁合金薄板试样表面进行冲击强化实验。实验结果表明,晶粒得到明显细化,晶粒大小由20μm左右细化到10μm左右,试样表面激光诱导的残余压应力高达-126 MPa。室温下通过三点加载的方法,对激光冲击、局部区域激光冲击以及未激光冲击的试样在去离子水中进行了应力腐蚀试验,对其断口进行了宏观和微观分析,表明激光冲击能够抑制应力腐蚀裂纹的产生和扩展。

In order to study the effect of laser shock processing（LSP） on the properties of magnesium alloy,according to the laser technology parameters after optimization,Rolled AZ31B magnesium alloy sheets surface were processed with Nd∶glass laser.Test results showed that grain is refined obviously,grain size changes from about 20 μm to 10 μm.Residual compressive stress induced by LSP reached up to-126 MPa.At room temperature,through three points loading method,samples performed by LSP,local regional LSP and without LSP were immersed in deionized water to carry out stress corrosion experiment.Macroscopical and microcosmical analysis was applied to its fracture surface.It shows that LSP completely prevents stress corrosion cracking（SCC） initiation for AZ31B in deionized water,and it indicats that LSP inhibits the propagation of the SCC crack.