Comparison of Aluminum Based Alloys Reinforced with Intermetallic Developed by Powder Metallurgy and Arc Melting Routes

Abstract

In this work, Al-Ti alloys were prepared using metallic powders of Al and Ti via Powder Metallurgy (PM) and Arc Melting (AM) route. Four chemical compositions including pure aluminum were studied. Metallic powders were mixed with three compositions, Al-5Ti, Al-10Ti and Al-10Ti-2SiC. All the compositions were in atomic percentage. In case of PM, samples were pressed uniaxially at 170 MPa to fabricate 10 mm diameter compacts followed by pressure-less sintering at 620°C under argon atmosphere for 4 hr. Pure Al showed densification up to 96% whereas sample with 5 at.% Ti decreased in densification to 90%. For samples with 10 at.% of Ti and with 2 at.% SiC, densification values were 92% and 93%, respectively. In the case of AM method, the process was carried out under vacuum in Argon atmosphere followed by homogenization at 600°C for 1 hr. The resulting microstructure and composition of samples were analyzed. X-ray diffraction (XRD) results confirmed the formation of TiAl₃ intermetallic phase in the alloy. The mechanical test used to assess samples performance was hardness. Hardness results showed a strong increase in hardness with increasing Ti contents and SiC addition for both types of samples. The developed Al-Ti and Al-Ti-SiC alloy exhibit better hardness properties and have the potential to be used for light-weight materials applications.

Key-words:
Arc melting; Powder metallurgy; Intermetallics; Phase constitution