Effects of ultrasonic vibration on microstructure and wear properties of laser in-situ synthesized TiB2-TiC/Al composite coatings

In-situ particle reinforced aluminum composite coatings were fabricated on 7075 aluminum alloy by ultrasonic-assisted laser alloying. The coatings consisted of Fe4 Al13 , TiB2 , TiC, Cr7 C3 , Cr2 B, and alpha-Al. TiB2 and TiC were well bonded to the alpha-Al interface, with interfacial mismatch rates of 5.8 % and 6.8 %, respectively. Ultrasonic vibration did not alter the phase structure but promoted the synthesis of more in-situ reinforcements and slightly increased surface roughness. Higher ultrasonic power led to increased coating depth and dilution rates due to intensive convection. Compared with the distinct enrichment observed without vibration, ultrasonic assistance resulted in more uniform elemental distributions. The cavitation and acoustic flow effects refined the intermetallic compounds and in-situ reinforcements, improving their distribution. An ultrasonic power exceeding 3,0 0 0 W further broke needle-like intermetallic compounds into finer particles. The ultrasonic-assisted coatings presented higher and more uniform microhardness values and superior wear resistance. The primary wear mechanism for all the coatings was abrasive wear, whereas the coatings without ultrasonic vibration exhibited more severe wear. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.