Correlation of Mechanical and Tribological Properties of Zn-40Al-2Cu-2Si Alloy

An attempt was made to correlate mechanical (hardness and ultimate tensile strength) and tribological properties (friction coefficient, working temperature, wear volume and average surface roughness) of Zn-40Al-2Cu-2Si alloy which was prepared by permanent mold casting. The tribological properties of the alloy were determined using a block-on-cylinder type wear test machine. The relationships between the mechanical and tribological properties of the alloy determined by linear regression analysis were observed to be expressed by linear or straight-line equations. The correlation coefficients of these relationships were found to be between 0.94 and 0.99. These linear equations indicate that the friction coefficient and the wear volume of this alloy can be calculated in terms of either its hardness or tensile strength under the given working conditions. These linear relationships also showed that as the hardness and the tensile strength of the alloy increase the friction coefficient, working temperature, and wear volume of it decrease but its average surface roughness increases. These observations were explained in terms of the microstructure and mechanical properties of the alloy, adhesion theory of friction and the Archard wear law. The equations obtained by this correlation can also be used for the selection of Zn-40Al-based alloys for bearing applications.