本文采用表面裂纹法测试了LD10CS 氩弧焊、氦弧焊及不同工艺的四种焊接接头的断裂韧性。结果表明,焊缝、半熔化区的断裂韧性值最低。热影响区也有不同程度的下降,其变化规律是与焊接工艺,特别是与热输入量有很大关系。用金相、断口形貌分析方法进行了初步探讨。焊缝区是典型的铸造组织,失去了变形铝合金热处理强化的特点。半熔化区是沿晶界发生低熔点共晶物熔化然后凝固的区域。该两区不可避免地会有一些焊接缺陷,因此韧性值最低。热影响区相当于进行了不同程度的退火,所以韧性值也引起了不同程度的降低。 In this paper, the fracture toughness of four kinds of welded joints of LD10CS TIG welding, helium arc welding and different processes were tested by surface crack method. The results show that the fracture toughness of the weld and semi-molten zone is the lowest. Heat affected zone also has varying degrees of decline, the variation is with the welding process, especially with the heat input has a great relationship. Metallographic, fracture surface morphology analysis method was initially discussed. Weld zone is a typical cast structure, losing the heat treatment of deformed aluminum alloy enhanced features. The semi-molten zone is a zone where the low-melting eutectic melts and then solidifies along the grain boundaries. The two regions inevitably have some welding defects, so the lowest toughness value. The heat affected zone is equivalent to varying degrees of annealing, so the toughness value also caused varying degrees of reduction.