Thermomechanical stability of a carbon fiber-reinforced aluminum matrix composite fabricated by spark plasma sintering in various pulse conditions

•Al–CF composite was fabricated by SPS in various pulse conditions.•The thermal expansion behavior became elastic by the interfacial Al4C3 formation.•The elastic thermal expansion disappeared when 500 μm-long fibers were used.•Long-time SPS provided the stable thermal expansion to Al–long CF composite.

We investigated the relative thermal expansion of a carbon fiber-reinforced aluminum matrix (Al–CF) composite fabricated by spark plasma sintering (SPS) in various pulse conditions, and attempted to create aluminum carbide (Al4C3) at the aluminum/carbon fiber (Al/CF) interface by means of controlled annealing. The thermal expansion behaviors of Al–CF composites became elastic after annealing, despite the brittleness of the annealed Al–CF composite fabricated in the pulse condition which provided higher maximum intensity peaks of voltages and currents than others did (3:3). Although this elastic thermal expansion behavior disappeared when longer fibers were used, longer sintering time retrieved it. The thermal expansion behavior of Al–CF composite remained plastic under the pulse condition which provided lower maximum intensity peaks of voltages and currents (24:1). In Al–CF composite, the variation of SPS pulse condition controls the Al/CF interfacial condition and the quantity of Al4C3 at Al/CF interface after annealing, and determines the thermal expansion behavior of Al–CF composite.