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通过拉伸、硬度试验以及金相分析,对铝合金6061焊接接头的软化和强化机理进行了研究。结果表明:热处理前焊接接头强度为175 MPa,经(525±5)℃×2 h固溶+(165~175)℃×8 h时效热处理后,焊接接头强度提高至236MPa,HAZ的硬度得到明显改善,拉伸试验断裂位置由HAZ转至焊缝,固溶+时效热处理使得焊缝区和HAZ析出大量弥散与基体共格的强化相,使焊接接头的强度、硬度显著提高。
The mechanism of softening and strengthening of 6061 aluminum alloy welded joints was studied by tensile test, hardness test and metallographic analysis. The results show that the strength of welded joints before heat treatment is 175 MPa, the strength of welded joints increases to 236 MPa after heat treatment at (525 ± 5) ℃ for 2 h and heat treatment at 165-175 ℃ for 8 h, and the hardness of HAZ is obviously The tensile strength and hardness of the welded joint were improved obviously. The fracture location of the tensile test was changed from HAZ to the weld. The solution treatment and aging treatment resulted in a large amount of strengthening phase dispersed in the weld zone and HAZ.