首页|Vacuum diffusion bonding of TC4 titanium alloy and T2 copper by a slow cooling heat treatment
Vacuum diffusion bonding of TC4 titanium alloy and T2 copper by a slow cooling heat treatment
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NSTL
Elsevier
TC4 titanium alloy was joined to T2 copper through vacuum diffusion bonding by a two-step slow cooling heat treatment in the vacuum furnace, which could reduce the residual stress and avoid the interface cracking from the large difference in linear expansion coefficients between titanium and copper. The effect of bonding temperature and bonding time on the microstructure and mechanical properties of the joint was investigated. The through crack formed at the interface with traditional cooling process, but disappeared with this two-step slow cooling process. The typical interfacial microstructure of bonded joints was beta-Ti+Ti2Cu+Ti3Cu, Ti2Cu, TiCu, TiCu2, TiCu3 and TiCu4 phases, in diffusion zones I to VI at bonding temperature below 880 degrees C. The joints obtained by the traditional cooling process failed during natural aging, with nearly null shear strength. The maximum shear strength of joints at 840 degrees C for 45 min by the slow cooling heat treatment reached 111 MPa. The growth activation energy obtained from zones I to VI was 190 kJ/mol, 446 kJ/mol, 240 kJ/mol, 147 kJ/mol, 849 kJ/mol and 79 kJ/mol, respectively. Fracture occurred mainly in the interface of TiCu and TiCu2 phases, with many dimples, revealing clearly ductile mode. Cu element near the interface had a larger diffusion capacity and diffused faster than Ti element in the diffusion process. The results in this paper provide an effective strategy for the joining of titanium alloy and copper in high precision friction components of aerospace engines.
NSTL
Elsevier
