Eliminating embrittlement of GH4065A superalloy at intermediate temperature by a novel grain boundary strengthening mechanism

Intermediate temperature embrittlement (ITE) exists widely in Ni-based superalloys, which seriously restricts the processing and service properties of alloys. The ITE of a Ni-based wrought superalloy GH4065A was eliminated by long-term aging treatment. With the extension of aging time, the fracture characteristics of the alloy changed from intergranular fracture to dimple. EDS and AES observations showed that the intergranular diffusion and segregation of W and Mo elements increased the grain boundary strength of the long-term aging alloy. Intergranular M6C carbide precipitates have also been shown to be beneficial for plastic deformation.

Automated summary

Intermediate temperature embrittlement (ITE) is widely present in Ni-based superalloys, which significantly restricts the processing and service properties of these alloys. The ITE in a Ni-based wrought superalloy GH4065A was eliminated through long-term aging treatment. With prolonged aging time, the fracture characteristics of the alloy transitioned from intergranular fracture to dimple fracture. EDS and AES observations revealed that intergranular diffusion and segregation of W and Mo elements enhanced the grain boundary strength of the long-term aging alloy. Intergranular M6C carbide precipitates have also been found to promote plastic deformation.