Effect of the Welded Zone Property on Behavior of a Dissimilar Superalloys Friction Joint under Creep Loading at Elevated Temperature - A Simulation Approach

Abstract

The forged superalloy Inconel 718 and cast superalloy Mar-M247 were joined via friction welding. The welded zone was recrystallized and formed a thin representative layer on the forged superalloy side adjacent to the interface. The effect of the creep property of the welded layer on the behavior of the joint under creep loading was investigated via numerical simulations. Despite the welded layer being relatively narrow (approximately 200 mm), it significantly effects the stress state and the creep damage parameters in and around the welded zone. When the creep rate of the welded layer is lower than that of the base alloy, the stress concentration is dramatically increases adjacent to the interface. However, the creep rate of the welded layer creep rate is higher than that of the base alloy, the interface stress concentration is reduced. The creep strain and stress exhibited an out-phase relation.