Diffusion bonding between TZM alloy and WRe alloy by spark plasma sintering

Highlights: • TZM alloy and WRe alloy was well bonded by SPS method without interlayers. • The TZM/WRe interface was free from intermetallics, discontinuities, microcracks and pores. • The TZM/WRe joint bonded at 1500 °C obtained sufficient diffusion and exhibited the best mechanical properties. • The TZM/WRe joint withstood 1500 times of repeated thermal shock and maintained high strength after thermal shock. Successful solid-state diffusion bonding was achieved between TZM alloy and WRe alloy without interlayers using spark plasma sintering (SPS) in the temperature range of 1300–1600 °C for 30 min. Both the TZM and WRe alloys recrystallized during the bonding process. There were no intermetallics, discontinuities, microcracks, or pores, and sufficient diffusion occurred in the TZM/WRe joint bonded at 1500 °C for 30 min. The TZM/WRe joint bonded at 1500 °C for 30 min exhibited excellent mechanical properties (shear strength of 498 ± 32.5 MPa and tensile strength of 475 ± 19.8 MPa) and thermal shock performance. The fracture morphology after shear and tensile test was both characterized as mixed transgranular cleavage and intergranular rupture. The TZM/WRe joint (1500 °C/30 min) was free from cracks and maintained high strength after experiencing repeated thermal shock 1500 times, and this was due to negligible residual thermal stresses and further diffusion in the TZM/WRe interface during the thermal shock process.