Improving the Surface Integrity and Tribological Behavior of a High-Temperature Friction Surface via the Synergy of Laser Cladding and Ultrasonic Burnishing

Abstract

Quite a lot of engineering friction components serve at high temperatures, and are thus required to have excellent friction and wear resistance. The said study aims to fabricate high-wear-resistance coating on ordinary low-cost materials, achieving the low-cost manufacturing of some high-end friction components that are usually made with expensive solid alloys. The coating was prepared via laser cladding with a sort of widely used Fe-based self-fluxing alloy powder. The chosen substrate material was forged 42CrMo, which is popular in high-temperature friction engineering applications. In order to achieve the best possible high-temperature friction and wear properties, the prepared coating was turned and then ultrasonic burnished. Three samples, i.e., the substrate sample, the cladded sample without burnishing, and the cladded sample with burnishing, were prepared. For the three samples, the surface characteristics and friction properties at a 200 °C temperature were compared and investigated. According to the results, the cladded sample with burnishing exhibited the best surface finishing and friction behavior. Ultrasonic burnishing after cladding led to a further hardness improvement of 15.24% when compared with the cladded sample without burnishing. Therefore, ultrasonic burnishing is an effective low-cost post-treatment method for a wearable coating serving at a high temperature.