(中南大學(xué) 高性能復(fù)雜制造國家重點(diǎn)實(shí)驗(yàn)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(yīng)力的影響，試驗(yàn)應(yīng)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(yīng)用X射線衍射法對焊縫的表面殘余應(yīng)力進(jìn)行了測量，并與相同參數(shù)、工藝條件下攪拌摩擦焊殘余應(yīng)力進(jìn)行對比。結(jié)果表明：轉(zhuǎn)速1 200 r/min、焊速160 mm/min時(shí)，超聲輔助攪拌摩擦焊縱向殘余應(yīng)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(diǎn)縱向殘余應(yīng)力分布更加均勻化，波動(dòng)量降低。超聲輔助攪拌摩擦焊對焊縫橫向殘余應(yīng)力影響很小，應(yīng)力水平與攪拌摩擦焊相當(dāng)。在相同轉(zhuǎn)速下，隨著焊接速度的提高，焊縫的縱向殘余應(yīng)力也隨之提高。
關(guān)鍵字: 超聲輔助攪拌摩擦焊；殘余應(yīng)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
