Enhancing corrosion and wear resistance of a 7075 aluminum alloy via depositing TC4 coating

Abstract

Aluminum alloys have been widely used in engineering due to their high strength and low density. However, their poor corrosion and wear resistance have largely limited their application in marine equipment. This study successfully improved the corrosion and wear resistance of a typical 7075 Al alloy by depositing a high-performance TC4 titanium alloy coating using in-house annular laser cladding equipment. Microstructural investigations revealed that the defect-free TC4 coating is metallurgically bonded to the 7075 Al alloy substrate along with excellent bond strength. Electrochemical test results showed that compared to the hot-forged 7075 Al alloy and hot-forged double-phase TC4 bulk alloy, the TC4 coating exhibits superior corrosion resistance due to its net-basket α-single-phase microstructure. Further, wear testing results showed that the coefficient of friction and wear volume of the TC4 coating are far lower than that of 7075 Al alloy. The enhanced wear resistance is closely related to the high hardness of the TC4 coating and its excellent fatigue-wear resistance. Therefore, this work can serve as a reference to improve Aluminum alloys' corrosion and wear resistance by depositing Titanium alloy coatings using the annular laser cladding process, which shall widen the potential applications of Aluminum alloys in marine equipment.

Keywords

• Aluminum alloys
• Annular laser cladding
• TC4 coatings
• Corrosion resistance
• Wear resistance