The SEM observations show that the fracture surface of LF6 alloy and welded joint exhibits hybrid tough fracture of dimple and tear ridge, and dimple becomes tiny and uniform with the decrease of temperature.

• 拉伸试样断口形貌分析结果显示 ,LF6合金及焊接接头的拉伸试样断口均为韧窝和撕裂棱混合型韧性断口 ,韧窝随温度的降低而变得细小、均匀