EFFECT OF TIC AND B4C ON MECHANICAL PROPERTIES OF AA7075 ALLOY FABRICATED BY POWDER METALLURGY

Abstract

In this work, aluminum metal matrix composites (AMMCs) were fabricated by usingpowder metallurgy. AA7075 powder is reinforced with two different ceramic particles(TiC,B4C) with different weight fractions (2.5, 5, 7.5 and 10 wt.%). The composites wereproduced by powder metallurgy by preparing the powder, mixing, compacting andsintering. The particle size of unreinforced AA7075 about 100μm, while particle size ofeach TiC and B4C about 150 μm. The mixing process was done by planetary mixing setuprotating at 250 rpm for 2hr. by adding zinc stearate as an activator material with steel ballmilling. However the mixture was compacted by hydraulic uniaxial press type (LeyboldHarris No.36110) about 200 kg/cm² according to (ASTM-D 618). After compactingprocess, the mixture sintered at 475 °C for 2hr. by using electrical furnace with argonatmosphere.There are many examinations and tests were carried out for the synthesized compositesmaterial (AA7075/ TiC and AA7075/ B4C) such as examination of the microstructure,mechanical tests such as hardness and compressive strength, physical tests such asdensity and porosity.The results of this work showed that improving in physical properties (theoreticaldensity, experimental density, porosity) and mechanical properties (Rockwell hardnessand Compressive strength)