ABSTRACT

Argon–arc welds of GH 4169 were produced. Microstructural observations and microhardness tests were performed to distinguish the different regions of the weld. The fatigue crack propagation (FCP) behaviours of the different locations were investigated at 650°C compared with that at 25°C. Besides, the fracture surfaces were observed by scanning electron microscopy (SEM) and the influences of temperatures and regions on FCP behaviour of GH 4169 argon–arc welded joint were discussed. The welds showed excellent high-temperature resistance to FCP, which related to the columnar crystals formed in the fusion zone. Besides, the FCP rates of welded samples were accelerated at 650°C and the failure mode changed from mixed transgranular and intergranular fracture to wholly intergranular fracture.

摘要

产生了GH 4169的氩弧焊。进行了显微组织观察和显微硬度测试，以区分焊缝的不同区域。研究了在650°C与25°C下不同位置的疲劳裂纹扩展（FCP）行为。此外，通过扫描电子显微镜（SEM）观察断裂表面，并讨论了温度和区域对GH 4169氩弧焊接头FCP行为的影响。焊缝显示出优异的抗FCP高温性能，这与熔合区形成的柱状晶体有关。此外，焊接样品的FCP速率在650°C时加速，破坏模式从混合的沿晶和沿晶间断裂转变为整个沿晶断裂。