(中南大學 高性能復雜制造國家重點實驗室，長沙 410083)
摘 要: 為了研究超聲輔助攪拌摩擦焊對焊縫殘余應力的影響，試驗應用20 kHz的超聲波輔助攪拌摩擦焊焊接了1.8 mm厚2024-T4鋁合金，焊后應用X射線衍射法對焊縫的表面殘余應力進行了測量，并與相同參數(shù)、工藝條件下攪拌摩擦焊殘余應力進行對比。結果表明：轉速1 200 r/min、焊速160 mm/min時，超聲輔助攪拌摩擦焊縱向殘余應力比攪拌摩擦焊平均降低38 MPa(降低28.5%)。超聲輔助攪拌摩擦焊沿焊縫方向各點縱向殘余應力分布更加均勻化，波動量降低。超聲輔助攪拌摩擦焊對焊縫橫向殘余應力影響很小，應力水平與攪拌摩擦焊相當。在相同轉速下，隨著焊接速度的提高，焊縫的縱向殘余應力也隨之提高。
關鍵字: 超聲輔助攪拌摩擦焊；殘余應力；2024鋁合金
（State Key Laboratory of Complicated Equipment Design and Extreme Manufacturing, Changsha 410083, China）
Abstract:To investigate the effect of ultrasonic assisted friction stir welding (UAFSW) on residual stress of weld line, 1.8 mm thick 2024-T4 aluminum alloy plates were welded by UAFSW with 20 kHz ultrasonic, and the residual stress of UAFSW was measured by X-ray diffraction and compared with that of friction stir welding (FSW) under the same process parameters. The results indicate that when the stirring rate is 1 200 r/min and the welding speed is 160 mm/min, the longitudinal residual stress of UAFSW reduces 38 MPa compared with that of FSW on average, which is decreased by 28.5%. And the longitudinal residual stress along the weld line of UAFSW is much more even than that of FSW. UASFW has small impact on the transverse residual stress, which is nearly equal to that of FSW. The transverse residual stress increases as the welding speed increasing at a constant rotation rate.
Key words: ultrasonic assisted friction stir welding; residual stress; 2024 Al alloy
