Wetting tuning of Al/B4C interface via femtosecond laser irradiation

The Al/B4C composites are widely used in aerospace, automotive, military and energy industries, which combine the mechanical properties of Al metal and B4C ceramics. To achieve the best composite performance, it is crucial to overcome the poor wetting between the two materials. It is well known that surface micro-nano structures can affect wetting. However, the high brittleness and hardness of B4C make it challenging to process. In this paper, we proposed a novel approach to create hierarchical micro-nano surface structures on B4C by femtosecond laser irradiation. Surface morphology, phase change, and valence bond structure before and after irradiation were characterized respectively. The wetting of B4C was characterized in terms of high-temperature metal melt wetting. Under high photon energy impact, carbon elements were precipitated, leading to forming a boron-rich phase. This new phase possesses higher chemical reactivity and is capable of promoting reactions with Al. Compared with the contact angle of the untreated sample, the contact angle decreased by 24°. This work demonstrates that femtosecond laser irradiation is a sustainable and concise technology to improve high-temperature wetting, providing a new idea for enhancing the wetting of metal/ceramic systems.