High-temperature tensile behavior of diffusion-welded hastelloy X

Changes in the material properties of alloys subjected to diffusion welding need to be analyzed to increase the adoption of compact heat exchangers in American Society of Mechanical Engineers standards. Hastelloy X was diffusion-welded in this study following a procedure recently developed by the authors. A metallographic study showed that the interface was discernible with some grains migrated across the interface. Satisfactory tensile properties were obtained at 25 °C, but the tensile samples were fractured at/near the interface with ∼40 % of tensile elongation in the tensile tests. The minimum strength reduction factors of the yield strength and tensile strength were 0.799 and 0.843, respectively. Dimples were extensively observed on the fracture surfaces, but the fracture surfaces were predominantly flat owing to the remnant Mo-rich M6C carbides (stringers).