Effect of Zinc Content on the Microstructure and Mechanical Properties of the Al-(5-50)Zn Alloys

In this study, ten binary aluminum-zinc alloys containing zinc in different ratios between 5 and 50% by weight were produced by permanent mold casting method. The microstructures of the produced alloys were examined in light microscope. X-ray diffraction (XRD) studies were carried out to determine the phases in the microstructure of the alloys. The findings show that the microstructure of the alloys up to 15% zinc is composed of aluminum-rich α phase and the zinc in the alloy completely dissolves in this phase. It was also showed that when the zinc content exceeds 15%, besides the α-phase, the zinc-rich η phase begins to form, and when the zinc content exceeds 25%, the α-phase grows dendritically. The hardness, tensile, and compression strength values ？？of the alloys increased continuously with increasing zinc content but after the % 30 zinc content tensile and compression strength values decreased. The changes in the microstructure and mechanical properties of the alloys were discussed based on their solidification behaviors and structural changes