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采用对接形式对7075-T651铝合金板进行了搅拌摩擦焊接,并采用盲孔法对其接头的残余应力分布规律进行了研究。结果表明,应力曲线为“M”型,焊核区最小,在邻近轴肩处最大。在焊接速度200 mm/min下,焊核的纵向残余应力为压应力。根据不同焊接速度下残余应力分布,发现随着焊接速度的提高,纵向残余应力增大,最大值从136MPa(200 mm/min)增大到275 MPa(300 mm/min)。另外,后退侧的残余应力比前进侧的大,随着焊接速度的减小,残余应力在前进侧与后退侧的差值减小。接头不同位置的微观组织分析表明,前进侧和后退侧不同的微观形貌也反应了残余应力的不对称性分布。
The friction stir welding of 7075-T651 aluminum alloy plate was carried out by using the butt joint method, and the residual stress distribution of the joint was studied by blind hole method. The results show that the stress curve is of the “M” shape with the smallest nugget area and the largest adjacent shoulder. The longitudinal residual stress of the weld core is compressive stress at a welding speed of 200 mm / min. According to the distribution of residual stress at different welding speeds, it is found that with the increase of welding speed, the longitudinal residual stress increases and the maximum increases from 136 MPa (200 mm / min) to 275 MPa (300 mm / min). In addition, the residual stress on the retreating side is larger than that on the advancing side, and as the welding speed decreases, the difference between the residual stress on the advancing side and the retreating side decreases. Microstructural analysis of the joints at different locations shows that the different microstructures on the forward and reverse sides also reflect the asymmetric distribution of residual stresses.