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In this paper, 50 ... 680 nm thick AlN-Al2O3 coatings are deposited by magnetron sputtering on the surface of a steel substrate and a piece of copper is melted on top of the ceramic. Upon heating the ceramic layer is cracked, and the phase inversion of the two top phases from steel/ceramic/copper configuration to the steel/copper/ceramic configuration takes place within 30 s of liquid time of copper. This phase inversion process is accompanied by a Gibbs energy change of about − 1.78 J/m2, due to good wettability of solid deoxidized steel by liquid copper in contrary to poor wettability of the ceramic by the copper. When copper is melted on AlN-Al2O3 coating with its thicknesses smaller than a critical value of about 170 ± 60 nm, liquid copper droplets hanging down into the cracks within the ceramic reach the solid steel surface at the bottom of the cracks, thus the flow of Cu down along the cracks is enabled. However, when copper is melted on AlN-Al2O3 with its thickness larger than the critical value of 170 ± 60 nm, Cu first forms a non-wetting droplet on top of the ceramics, and only after a certain incubation time it starts flowing down the cracks. This incubation time was found to depend linearly on the thickness of the ceramic, as cracks are filled from the bottom upwards by liquid copper via the evaporation–condensation mechanism. By the end of the process, the steel/copper/ceramic configuration is further stabilized by gravity. [ABSTRACT FROM AUTHOR]

Sintering of aluminum alloys is usually performed by the formation of a liquid phase. A liquid phase in 2xxx series alloys is formed from α+Al2Cu eutectic. In this work, the influences of trace elements like Sn or Pb, and the addition of a ceramic reinforcement, such as TiCN, on 2014 alloys are studied. Mechanical properties as well as a microstructural study show improved results. [ABSTRACT FROM AUTHOR]

Transient liquid-phase (TLP) bonding of aluminium-based metal matrix composite (MMC) and Al2O3 ceramic materials has been investigated, particularly the relationship between particle segregation, copper interlayer thickness, holding time and joint shear strength properties. The long completion time and the slow rate of movement of the solid–liquid interface during MMC/Al2O3 bonding markedly increased the likelihood of forming a particle-segregated layer at the dissimilar joint interface. Preferential failure occurred through the particle-segregated layer in dissimilar joints produced using 20 and 30 μm thick copper foils and long holding times (≥20 min). When the particle-segregated layer was very thin (<10 μm), joint failure was determined by the residual stress distribution in the Al2O3/MMC joints, not by preferential fracture through the particle-segregated layer located at the bondline. Satisfactory shear strength properties were obtained when a thin (5 μm thick) copper foil was used during TLP bonding at 853 K. [ABSTRACT FROM AUTHOR]