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本文研究用表面裂纹法测试LD10cs铝合金板材焊接接头各部位疲劳裂纹扩展速率。结果表明:焊接接头各部位疲劳裂纹扩展速率随焊接热循环引起的金属组织变化而变化,有一定规律性。熔合线和焊趾处疲劳裂纹扩展速率较其他部位大。焊缝加强高的存在,引起焊趾处应力集中,使该处疲劳性能进一步恶化,成为焊接接头疲劳性能最差的部位。结合金相组织和扫描电镜分析,对影响焊接接头各部位疲劳裂纹扩展速率的各种因素作了较详细的探讨,并提出了改进焊缝质量的建议。
In this paper, surface crack test LD10cs aluminum alloy sheet welded joints fatigue crack growth rate. The results show that the fatigue crack growth rate of each part of welded joint varies with the change of metal structure caused by welding thermal cycle, and has certain regularity. The fatigue crack growth rate at fusion line and weld toe is larger than that at other locations. Weld to strengthen the high presence, causing the stress concentration at the weld toe, so that further deterioration of the fatigue performance at the weld joint fatigue performance of the worst parts. Combined with the analysis of microstructure and scanning electron microscope, various factors that affect the fatigue crack growth rate of welded joints are discussed in detail, and some suggestions to improve the weld quality are put forward.