采用搅拌摩擦方法对预制裂纹的2A12铝合金进行修复,并研究了裂纹放置位置对修复试样疲劳性能的影响.结果表明:预制裂纹试样经搅拌摩擦修复后裂纹愈合,裂纹位于前进侧修复后疲劳寿命最低,位于中间修复时疲劳寿命最高.断口分析表明前进侧修复试样由于热塑性材料损失造成修复区分层,返回侧修复试样断口与裂纹位于中间修复断口较为平整;修复区热塑性材料呈旋涡状流动,有流向轴肩中心趋势,因此裂纹位于中间时修复效果最好,并且修复区晶粒由于动态再结晶得到细化.%2A12 aluminum alloy with pre-crack has been repaired by friction stir crack repairing technology,and the influence of setting position of crack on the fatigue performance were investigated.The results showed that the fatigue life was lowest when the crack was located in the advancing side,and maximum fatigue life was obtained when the crack was located in the middle.Fractography analysis showed that delamination defect was introduced between the repaired layer and the base material when crack was located in the advancing side while the fracture surfaces were relative fiat when the crack was located in the middle or the retreating side.Thermoplastic material flowed like vortex with material had a tendency to move to the shoulder center,as a result the repairing result was best when the crack was located in the middle.Grains in the repaired zone was refined by dynamic recrystallization.
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