مرکز منطقه ای اطلاع رساني علوم و فناوري - A Study on Manufacturability of Zinc-Aluminum (ZA) Alloys via Mechanical Alloying Process

Abstract :

Manufacturability through mechanical alloying (MA) of ZA-8, ZA-12, ZA-27 Zinc-Aluminum alloys with different chemical compositions was studied. For this purpose, MA processes were carried out by ‘SPEX’ type miller for up to 8 hours. Characterization, sintering microstructures and densities of produced ZA alloys were examined. In the experimental studies, steel balls which are 8 mm in diameters and with 10/1 ball-powder ratio was used. It was observed that when no lubricant is used, the alloying powders started to break up without flaky during the MA process. Depending on MA time, ZA alloying powders with different sizes were produced. These powders were characterized by scanning electron microscopy (SEM). Then Zinc-Aluminum powders were hot pressed in the mold under 625 MPa pressure at 320 °C and sintered at the same temperature. After the sintering process, densities of specimens were specified and SEM plus EDS studies were done for their microstructural characterizations. Optimum MA time was found to be 4 hours in terms of powder size in all ZA alloys. When original chemical composition of ZA alloys is taken into account, the ratio of A1 was higher than expected, whereas the ratio of Zn was lower. According to element distribution map results, it was seen that Cu was homogeneously distributed through the structure and Al and Zn were oxidized. The densities of ZA alloys after the MA process and under cold press conditions were higher than their densities after sintering.