Bulk-alloy microstructural analogues for transient liquid-phase bonds in the NiAl/Cu/Ni system

Transient liquid-phase (TLP) bonds between dissimilar materials can have co mplex microstructures that evolve both during holding at the bonding temper ature and on cooling. In this article, an examination is made of the feasib ility of producing bulk-alloy microstructural analogues for individual micr ostructural features of dissimilar material TLP bonds. The ultimate intent of this work is to enable the contribution of individual microstructural fe atures to the overall properties of TLP bonds to be determined. Specificall y, the article focuses on the production, characterization, and application s of microstructural analogues for TLP bonds in an NiAl/Cu/Ni model system. The article examines the use of five different cast Ni-Al-Cu alloys, toget her with heat treatment of selected materials, as bulk analogues for six di stinct microstructural regions of the NiAl/Cu/Ni bonds. Each of these analo gues is characterized in detail by transmission electron microscopy (TEM) a nd compared to the relevant target region of the bond. An initial examinati on is also made of the use of bulk alloys in aiding an understanding of pha se transformations and structure-property relationships in these bonds.