LD10cs 铝合金焊接接头疲劳裂纹扩展速率的研究

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。

A Study of the Fatigue Crack Propagation Rate of the Butt-welded Joints of Aluminium Alloy LD10cs

The fatigue crack propagation rate at different points of aluminium alloy LD10cs butt-welded joints, tested by method of surface flaw has been discussed in this paper. The results show that the fatigue crack propagation rate at different points of the welded joints regularly varies with metal structure change resulting form the heatcycling of welding. The fatigue crack propagation rate of the fusion line and weld toe are greater than that of the others. The existence of the weld reinforcement will cause stress concentration at weld toe, and give worse infuence on the fatigue properties of this point, Hence, the fatigue properties of the weld toe will be the worst at welded joints. The various factors that affect the fatigue crack propagation rate at different points of the welded joints have been investigated and examined using optical metallography and scanning electronic microscope tochniques in detail. The suggestion to improve the quality of the welded joint has been presented.