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分别对3种不同镁含量铝镁合金进行搅拌摩擦焊接,根据金属平板平面弯曲疲劳试验标准,对试样进行共振频率下振动疲劳寿命测试,并用显微镜观察试样裂缝扩展特征,分析镁含量对搅拌摩擦焊(FSW)焊缝共振疲劳寿命的影响。研究表明:含镁量较低(0.44wt%)的铝镁合金经搅拌摩擦焊后,振动疲劳寿命出现提升,由0.9×105提高至4.1×105;搅拌摩擦试样振动过程产生的滑移带,可有效降低裂缝传播的驱动力,从而提高试样的振动疲劳寿命;较高镁含量(4.32wt%)搅拌摩擦试样的裂缝传播,为穿晶传播和沿晶传播混合模式,是导致其振动疲劳寿命低的原因之一。
Friction stir welding was carried out on the three kinds of magnesium alloy with different Mg content respectively. According to the flat bending fatigue test standard of metal plate, the vibration fatigue life test of the sample was carried out at the resonance frequency. The crack propagation characteristics of the sample were observed with a microscope. Effect of Friction Welding (FSW) Weld Resonant Fatigue Life. The results show that the fatigue life of the Al-Mg alloy with low Mg content (0.44wt%) increases after friction stir welding, from 0.9 × 105 to 4.1 × 105. The slip band , Which can effectively reduce the driving force of crack propagation and improve the vibrational fatigue life of specimens. Crack propagation of the friction stir specimen with higher magnesium content (4.32wt%) is a mixed mode of transgranular and intergranular propagation, Vibration fatigue life is one of the reasons.