Microstructural and mechanical investigation of Transient Liquid Phase Bonding of Inconel 738 Nickel base superalloy to TiAl Intermetallic compound

Transient Liquid pahse (TLP) bonding was used to join nickel base superalloy Inconel 738 in as-castcondition to TiAl intermetallic compound by using two different interlayer MBF-30 and pure Cu with50micron thickness. TiAl intermetallic was casted of titanium and aluminum with 99.9% purity byVacuum Arc Melting(VAR) furnace. Bonding were carried out in vacuum atmosphere at temperaturerange between 1120-1150˚C with different bonding times. Bonding microstructure was studied by lightand scanning electron microscopes. Microstructural evaluation was depicted some intermetalliccompounds had been appeared. With bonding at higher temperatures or bonding times has beendisappeared or discontinued. By increasing bonding time, amount of eutectic structure was decreasedgradually and isothermal solidification was completed at 1150˚C and 10 minutes. Results show that themicrostructure of bond area has different complex composition and phases in spite of their discontinuities.Mechanical properties show that the hardness of the bonding area because of brittle boride and carbidephases that are formed in that area is higher than near the base materials areas.

Keywords:

Inconel 738 , Titanium aluminide , TLP Bonding , Intermetallic compound , Nickel base superalloy