Dimensional instability of LF21 aluminum alloy weldments at room temperature and after thermal cycles

The unstable dimensional distortion of LF21 aluminum alloy weldments at room temperature and after thermal cycles was studied by use of light interference and CMM. At the same time, distortion mechanism was analyzed from the viewpoint of mechanics and microstructure. Experimental results show that there exists obvious difference of unstable dimensional distortion between LF21 welded specimens under two conditions mentioned above. Under room temperature, dimensional variation of welded specimens will decrease gradually and finally tends to be stable during 130 h after welding. The relative elongation of welded specimen is 4.2×10 -5 . After thermal cycles, distortion of welded specimen is much larger than that at room temperature. After 11 thermal cycles, the dimension will tend to be stable. Dimensional unstable distortion of weldments mainly results from temperature condition, microstructure variation and relaxation of welding residual stress.

电磁脉冲焊接铜铝异种材料接头的组织与性能分析

采用电磁脉冲焊接方法,进行T3纯铜与LF21防锈铝的异种材料焊接试验,并测试与分析了显微组织、物相组成、表面硬度和力学性能。结果表明,该方法可获得较高质量的焊接接头,接头抗拉强度为137 MPa,达到LF21防锈铝母材的110%,达到T3纯铜母材的51%;焊接接头由α-Al固溶体相、Cu相和Cu Al2相组成。