Papers by Author: Robin A.L. Drew

Abstract: Transient Liquid Phase Bonding (TLPB) is a joining process that uses liquid as medium for the establishment of an interface between two faying surfaces. In TLPB, as opposed to brazing process, the careful selection of the interlayer materials and the use of a prolonged heat treatment, allows for isothermal solidification and results in interfaces possessing potential service temperature higher than the joining temperature itself. Such a process is attractive for joining ceramics to metals and composites. In this presentation, the applicability of TLPB for various systems: Si3N4/FA-129 iron aluminide alloy, Al2O3/Al2O3, Al-Al2O3/Al-Al2O3, Al-Al2O3/Al-SiC and Al-Al2O3/Al. Results on the interface formation, interfacial microstructure and mechanical properties will be presented. A comparison of the TLPB joint properties with traditional joining for similar systems will be illustrated.

Abstract: A novel ceramic-metal composite with continuous interconnected ceramic and metal phases has been fabricated from sintered porous particulate AlN preforms infiltrated with magnesium. The 48 vol. % AlN composites are fabricated by pressureless infiltration in argon in the temperature range of 870 °C to 960 °C. An increase in the infiltration rate is observed as the temperature increases. Results on the mechanical characterization of the composites indicate an elastic modulus of 90 to 110 GPa and hardness of 70 to 80 HRB. The tensile strength calculated by the shear punch test method ranges from 260 to 390 MPa. As a general rule, it is observed that the lower the infiltration temperature, the higher the tensile strength. The linear coefficient of thermal expansion of the infiltrated composites in the temperature range of 215 to 315 °C is 7.65 x 10-6 °C-1. This value is lower than those found for similar Al/AlN composites reported in the literature.