Metallurgical Study of TLP-Bonding of Ni-Base Single Crystal Superalloy, CMSX-2

Transient Liquid Phase Bonding of Ni-Base Single Crystal Superalloy (Report 2)

Abstract

The dissolution of base metal and isothermal solidification behaviors of Ni-base single crystal superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 and F-24 insert metals. TLP-bonding of CMSX -2 was carried out at 1373-1548 K for 0-19.6 ks in vacuum. The (001) orientation of each test specimen was always aligned perpendicular to the bonding interface. The dissolution width of base metal at the bonding temperature increased when the bonding temperature and holding time were increased. The dissolution phenomena of base metal into melted insert metal could be expressed by Nernst-Brunner's theory. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process. Borides were formed in the bonded layer during TLP-bonding operation. The amount of microconstituents in the bonded layer after isothermal solidification decreased with bonding temperature, and the microconstituents in the bonded layer disapperaed at the bonding condition of 1523 K × 1.8 ks when MBF-80 insert metal was used.