Hardness and corrosion behavior of Al-Ti-Cu alloys fabricated by powder metallurgy technique

The present study reports the manufacturing, hardness, and corrosion behavior of Al-20%Ti-6%Cu and Al-15%Ti-6%Cu alloys, which were successfully fabricated by powder metallurgy technique. The microstructure of synthesized alloys was studied, and the corrosion tests of the sintered samples were carried out in a 1.5 M HCl solution at 25 °C using potentiodynamic polarization curves. X-ray diffraction analyses were employed to examine the phase structure of fabricated alloys. Scanning electron microscopy (SEM) was used in combination with energy-dispersive X-ray spectroscopy (EDS) to investigate the surface morphology and the elemental composition of the corroded surface of all manufactured alloys. The results revealed that the hardness increased significantly as the titanium content increased in the alloys, from 15 to 20 wt%. The hardness finding showed that the hardness of Al-20%Ti-6%Cu sintered for 5 h increased in comparison to Al-15%Ti-6%Cu sintered for 3 h. Maximum hardness was reported with the addition of 20 wt% Ti to the alloy after sintering at 550 °C for 5 h. The polarization curve data showed that the corrosion behavior of alloys was improved with the increasing Ti content and also confirmed that alloys do not suffer pitting attacks. Moreover, SEM images revealed that the alloys fabricated with a higher amount of titanium and sintered for 3 h, exhibit an enhancement in resistance to corrosion. Furthermore, these alloys formed a substantial layer of corrosion products, preventing pitting on their corroded surfaces. Therefore, these alloys are a material of choice in many industrial applications, like aerospace and automobiles.