Transient liquid phase bonding of titanium to aluminium nitride

Titanium has been successfully joined to aluminium nitride AlN at a temperature as low as 795 °C, using Ag–Cu Cusil® commercial braze alloy. While reactive wetting and spreading proceeds at the AlN/braze alloy interface, chemical interactions develop at the titanium side rendering possible isothermal solidification of the joint. The determining factor in the solidification process is the fast formation of TiCu4 crystals by heterogeneous nucleation and growth in the liquid phase. As a consequence, the braze alloy is depleted in Cu and solid Ag precipitates. After annealing, the re-melting temperature of the resulting joint can be increased up to about 910 °C which is nearly 130 °C higher than the melting point of the starting braze alloy.