Microstructure and wear properties of laser cladding Ti–Al–Fe–B coatings on AA2024 aluminum alloy

In order to improve wear resistance of aluminum alloy, the in situ synthesized TiB2 and Ti3B4 peritectic composite particulate reinforced metal matrix composite formed on the 2024 aluminum alloy by laser cladding with a powder mixture of Fe coated Boron, Ti and Al was successfully achieved using 3 kW CW CO2 laser. The laser cladding coating present excellent bonding with aluminum alloy substrate. The chemical composition, microstructure and phase structure of the composite clad coating were analyzed by energy dispersive X-ray spectroscopy (EDX), SEM and XRD. The typical microstructure of composite coating is composed of TiB2, Ti3B4, Al3Ti, Al3Fe and α-Al. The surface hardness of cladding coating is increased with the amount of added Fe coated B and Ti powder which determines the amount of TiB2 and Ti3B4 peritectic composite particulate, and obviously higher than that of substrate. The wear tests were carried out using a FALEX-6 type pin-on-disc machine. The test results show that the composite coatings with the in situ synthesized TiB2 and Ti3B4 peritectic improve wear resistance when compared with the as-received Al substrate.