The Porosity and Hardness of Fe-18Al Alloy Added ZrO₂ Nanoparticles

The additive effect of ZrO₂ nanoparticles in Fe-18Al based alloys through the mechanical alloying process to the porosity and hardness was investigated. Results of microstructure observations showed that the only intermetallic Fe₃Al present as the major phase in the samples along with other phases which are very minor together with the presence of porosity that indicated by objects of dark color. The porosity tends to diminish with the addition of ZrO₂ nanoparticles. However, the porosity is still visible on the Fe-Al alloy with the addition of 2% additive and the higher compaction load especially in the surface area. The results of phase study by XRD confirmed the presence of the intermetallic Fe₃Al. It is shown that ZrO₂ nanoparticles are dispersed in the metal matrix. The presence of ZrO₂ also confirmed by SEMEDS. The fraction of pores that estimated based on the microstructure observation showed a decrease with an increase in volume fraction of ZrO₂ nanoparticles and the compaction load. The study concluded that the hardness of Fe-18Al alloys increased with a decrease in porosity which achieved in Fe-18Al alloy added with 2% ZrO₂ nanoparticles. The lowest porosity level is 0.17% and the highest hardness value is 352.59 HV.