Influence of nickel addition on the microstructure, mechanical, and wear properties of Zn-40Al-2Cu alloy; [Einfluss des Nickelzusatzes auf das Gefüge, die mechanischen und die Verschleißeigenschaften der Legierung Zn-40Al-2Cu]

To study the influence of nickel addition on the microstructure, mechanical and lubricated wear properties of Zn-40Al-2Cu alloy, one ternary and five quaternary Zn-40Al-2Cu-(0.5-2.5)Ni alloys were made by permanent mold casting. The wear behavior of these alloys was studied using a block-on-cylinder type test machine, after examining their microstructural and mechanical features. The microstructure of Zn-40Al-2Cu alloy was comprised of aluminum-rich α dendrites and a eutectoid α+η phase mixture. The addition of nickel caused the formation of intermetallic Al3Ni particles in the microstructure of this alloy. As the nickel content of alloys increased their hardness, friction coefficient, working temperature, and average surface roughness increased to certain extents but their strength, ductility, impact resistance, and wear volume decreased. However, the values of their wear volume and average surface roughness exhibited opposite changes with increasing nickel content. The worn surfaces of Zn-40Al-2Cu-Ni alloys were observed to be characterized by smearing and scratching marks. Furthermore, the wear and mechanical properties of these alloys were correlated, and the results were discussed in terms of their microstructural features. Finally, it may be concluded that the nickel addition adversely affects the ductility of Zn-40Al-2Cu alloy but increases its wear resistance.