Investigation of Ni effect on the microstructure and tensile properties of Al-12Zn-2.5Mg-2.5Cu aluminum alloy

In this study, the effect of Ni on the microstructure and tensile properties of Al-12Zn-2.5Mg-2.5Cu-0.05Ti aluminum alloy has been investigated. Microstructural examinations were conducted by optical and scanning electron microscopy, coupled with energy dispersive spectrometry. Microstructural studies showed that by adding Ni (from 0 to 5 wt. %) to the alloy, the volume fraction of precipitates increases. Also, increasing Ni content up to 3 wt. % showed an increase in ultimate tensile strength (UTS) values and marginal effect on ductility (% El.). The optimum amount of Ni was selected as 3 wt. %. SEM fractography of several fractured surfaces showed an overall brittle appearance with cracking along the grains.

Keywords:

Aluminum alloys , casting , microstructure , fractography