MICROSTRUCTURAL DEVELOPMENT AND MECHANICAL PROPERTY RELATIONSHIPS IN WIDE-GAP TRANSIENT LIQUID PHASE BONDING OF SINGLE CRYSTAL TO POLYCRYSTALLINE NICKEL-BASE SUPERALLOYS

摘要

This paper investigates the microstructure-mechanical property relationships in wide gap transient liquid phase (TLP) bonds, between the single crystal nickel-base superalloy CMSX-4 and two polycrystalline superalloys, IN 738 and IN 939, using wide-gap style composite interlayers of Niflex-110 and Niflex-115, in comparison with conventional BNi-3 foils. Composite interlayers resulted in the suppression of bondline boride formation. Results from shear testing and fractography indicated that ductile shear failure occurred along the bondline and that the extent of formation of g' on the bondline was the dominant factor in the determination of room-temperature shear strength of the bonds.