Indexed on: 25 Jan '08Published on: 25 Jan '08Published in: Tribology Letters
In this work, one ternary Al–40Zn–3Cu and seven quaternary Al–40Zn–3Cu–(0.25–5)Si alloys were synthesized by permanent mould casting. Their microstructure, mechanical and lubricated wear properties were investigated using appropriate test apparatus and techniques. As the silicon content increased the hardness of the alloys increased, but their elongation to fracture decreased. Tensile strength of the alloys decreased with increasing silicon content following a sharp decrease and a slight increase. Among the silicon-containing quaternary alloys the highest and the lowest tensile strength values (348 and 305 MPa) were obtained with the Al–40Zn–3Cu–2Si and Al–40Zn–3Cu–5Si alloys, respectively, while the base alloy (Al–40Zn–3Cu) exhibited a tensile strength of 390 MPa. However, the volume loss due to wear of the alloys increased with increasing silicon content after showing an initial increase and a sharp decrease. The lowest wear loss was obtained with the alloy containing approximately 2% Si which has the highest tensile strength among the quaternary alloys containing more than 0.25% Si. Wear surfaces of the alloys were characterized mainly by smearing indicating that adhesion is the dominant wear mechanism for the experimental alloys.