A Comparative Study of the Microstructure and Properties of Al2CrFe2Ni4Ti1.5 Coatings Fabricated by Oscillating Laser Cladding Under Pulsed and Continuous Modes

As high-end equipment manufacturing advances, demand for improved surface performance in critical components has increased. Laser cladding is an advanced surface strengthening technique that affords effective surface modification. During the laser cladding process, obtaining a fine grain microstructure usually helps to enhance the microhardness, wear resistance, and corrosion resistance of the cladding layer. However, conventional laser cladding often yields coarse columnar grains that limit further performance improvements, so process optimization to achieve grain refinement is necessary. In this study, oscillating laser cladding was combined with a pulsed-wave (PW) laser mode to deposit a fine-grained Al2CrFe2Ni4Ti1.5 high-entropy alloy cladding on Q550 steel substrates. Compared with continuous-wave (CW) laser cladding, the PW mode produced markedly refined grains and concomitant improvements in microhardness, wear resistance, and corrosion resistance. Specifically, the microhardness of the PW cladding layer reached approximately 673.34 HV0.5, the wear volume was approximately 0.06 mm3, the wear rate was approximately 0.21 × 10−4 mm3/N·m, and the corrosion current density decreased to approximately 1.212 × 10−5 A·cm−2. This work presents a novel approach for producing high-performance, wear-resistant, and corrosion-resistant high-entropy alloy cladding layers, and offers both theoretical insight and potential engineering applications.