The influence of the low expansivity interlayer on the cracking susceptibility and properties of AIN -copper joints brazed with Ag-Cu-Ti filler metal was examined. The thermal stress and heat conduction numerical analyses suggest that not only crack-free joints but also the superior thermal conductive joints can be produced by employing tungsten or molybdenum interlayer for AIN to copper joining. The cracking of AIN-OFC joints can be prevented by increasing the tungsten and molybdenum interlayer thicknesses above 0.8 mm and 2.0 mm, respectively. The tensile strength of AIN-OFC joints brazed at 1078 K for 120 s with 1.0 mm thick tungsten interlayer is approx. 50 MPa. AIN-W-OFC joints using Ag-Cu-Ti filler metal indicate the superior reliability for thermal fatigue and heat conduction.
