Effect of temperature on microstructure and physical properties of Zn-Al/SiC/Gr hybrid composites produced by current sintering

Effect of reinforcements with Silicon Carbide (SiC) and Graphite (Gr) on the thermal behavior of the Zinc (73 wt. % Zn)-Aluminum (27 wt. % Al) investigated by using mechanical alloying and then subsequent rapid current sintering technique. Also effect of thermal variations on microstructure and mechanical properties investigated. The mechanically ball milled Zn, Al particulates and Zn, Al 20 vol. % SiC (13 wt.%) and with various amounts of graphite (2.5 wt. %, 5.0 wt %, 7.5 wt. % and 10 wt. %). Mechanically alloyed particulates were cold compacted under constant pressure of 200 MPa with steel mold. The compacted structures were sintered at atmospheric conditions almost to the full density within 10 minutes using current sintering, in which the powders were heated by a low voltage (1.7-2.3V) and high amperage (1000 A) current and compressed simultaneously. Thermal expansion experiments were carried out on the unreinforced Zn-Al alloy, Zn-Al-SiC composites and Zn-Al-SiC-graphite hybrid composites by using a vertical sample arrangement dilatometer system. Before and after dilatometer test microstructures and mechanical properties were investigated with SEM and micro vickers indentation system respectively. Zn-Al alloys thermal stability were increased via addition of SiC and Gr into structure.