Microstructure and Properties of a Laser-Surface-Modified Mg-RE Alloys with Al-Si Powder

Magnesium alloys are renowned for their low density and high strength-to-weight ratio, making them widely utilized in aerospace and automotive manufacturing. This study aims to improve the properties of VW94 rare earth magnesium alloy using laser cladding Al-Si coating with coaxial powder feeding. The purpose is to improve its inherent low hardness and enhance its resistance to wear and corrosion. The obtained cladding layer mainly consists of Mg₂Si, Al₂(Gd,Y), Al₁₂Mg₁₇ and Al₃Mg₂ phases in the Al-Si coating. Evaluation of coatings includes microhardness testing and friction and wear testing. Furthermore, its corrosion resistance was evaluated through electrochemical corrosion tests. The formation of intermetallic compounds increases the hardness of the cladding layer to 260 HV_0.1, which is three times the hardness of the substrate. Specifically, the weight loss of substrate was approximately 6.1 × 10⁻⁴ g, which was about double that of the cladding layer's 3.5 × 10⁻⁴ g. The cladding layer formed a dense Al₂O₃ film, the corrosion potential increased from − 1.725 V to − 1.108 V, and the corrosion current density decreased from 1.763 × 10⁻⁵ A/cm² to 3.165 × 10⁻⁶ A/cm². The research results confirmed that laser cladding can significantly improve the surface properties of Mg-RE alloys.