Microstructural Characterization of TLPD bonded 6061-SiCp Composite

Microstructural development during transient liquid phase diffusion (TLPD) bonding of extruded aluminum-based metal matrix composite (6061-15 wt.% SiCp) using 50-μm-thick copper interlayer was investigated by optical microscopy, scanning electron microscopy (SEM) together with SEM-based energy dispersive x-ray spectroscopy (EDS). Microstructural changes in the joint region were examined for a bonding temperature of 560 °C with five different holding time (20 min, 1 h, 2 h, 3 h, and 6 h) under two different applied pressure (0.1 and 0.2 MPa). Kinetics of the bonding process was significantly accelerated in presence of reinforcement (SiC). This acceleration is attributed to the increased solute diffusivity through defects as well as decreased incubation time required for nucleation (SiC particles acting as nucleating agent).