ZA alloys by powder metallurgy production method, characterization and wear properties

In recent years, the use of zinc-aluminum based ZA alloys, which are known to have better qualities in comparison to traditional bearing alloys, is becoming more and more common. Among these qualities having high wear resistance and high specific strength, being, being economical and easy to produce, showing high tribological behavior under high speed working conditions, are the top ones. Due to these qualities zinc-aluminum based ZA alloys are more commonly preferred in bearing production.In this study, ZA-8-ZA-12-ZA-27 alloys with different compositions were aimed to produce through mechanical alloying method. Microstructural characterization and dry sliding wear behavior of these alloys were examined. Using Spex type mill and mechanical alloying method, changes in powder size were observed. Zinc-aluminum alloying powders produced in spex at different alloying times were hot pressed at 320 °C and sintered again at 320 °C. Micrsctructura characterization analyses were carried out by SEM and EDS. Dry sliding wear behavior of those ZA alloys were done on a pin-on-disc type wear machine.It was found that the pressing densities of ZA alloys were higher than those of sintering densities. The densities of these alloys decreased with increasing aluminum rate. The lowest wear occurred in ZA-27 alloy, whereas it was the highest in ZA-8 alloy according to the results of wear tests. The wear behavior of ZA alloys was affected by MA times. At first, the amount of wear decreased with an increase MA time; however, it increased after the 8-hour MA process.