Notch effect on creep damage for Hastelloy C276-BNi2 brazing joint

• Different notch types generate different stress distributions and creep damages.
• Bigger notch radius increases failure time for U-type while decreases it for C-type.
• The V-type notch is easier to generate creep damage failure.
• The failure time has a proportional relationship with notch angle.
• The brazing joint with higher stress concentration easily generates creep failure.

The brazed structures have geometrical discontinuities like fillets working as notches. These notches have great effect on creep crack initiation and propagation. This paper studies the notch effect on creep damage for Hastelloy C276-BNi2 brazed joint, and the effects of notch type, notch radius and notch angle on creep damage have been investigated. The results show that the creep damage initiates in the filler metal. Different notch types bring different stress states, and generate different stress triaxialities and equivalent creep strains (CEEQs), leading to different creep damages. The maximum creep damage is generated in the notch tip for V-type notch, while the maximum creep damage is located at 0.4 mm away from the notch tip for C-type notch. For U-type notch, the location of the maximum creep damage moves from the notch tip to the inside gradually as the notch radius increases. With the increase of notch radius and notch angle, the failure time of creep damage increases for U-type and V-type notches, while it decreases for C-type notch. The creep failure is prone to happen to V-type notch because it belongs to sharp notch.

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