【摘要】 利用扫描电镜观察了中强可焊AlZnMg合金焊接接头应力腐蚀断裂的特点。结果表明,应力腐蚀断裂的特点深受接头本身的抗应力腐蚀性能的高低和断裂位置的影响。抗应力腐蚀性能高的接头,主要在热影响区断裂,断口几乎是全由韧窝组成的韧性断裂;而抗应力腐蚀性能低的接头,主要在熔合线近傍断裂,断口全是沿晶的脆性断裂。抗应力腐蚀性能低的合金焊接后,在大气中长期存放沿熔合线发生的开裂,是由焊接应力引起的,断口是典型的脆性沿晶断裂。更多还原

【Abstract】 The stress-corrosion fracture behaviour of welded joints in the weldable Al -Zn-Mg alloys with medium strength have been observed by means of scanning electron microscopy . The results indicate that the characteristics of SC fracture are strongly influenced by the SC resistance of the welded joints and its fracture locations. While the joints with high stress-corrosion resistance are mainly fractured in the heat-affected zones and its fracture appears as ductile and almost composed entirely by dimples, the joints with low stress-corrosion resistance are mainly fractured by the fuse line and its fracture appears brittle and entirely intergranular. The cracking of alloy with very low stress-corrosion resistance,welded and stored in open air for a long time, is caused by the welded stress and such a fracture is a typical intergranular fracture.更多还原