Suspended water droplet confined laser shock processing at elevated temperatures

Abstract

The temperature-assisted laser shock process has application prospects in various manufacturing fields such as forming and surface strengthening. However, the large-scale application of this process is limited by the instability and failure of confinement medium at high temperatures (>300 °C). To address this problem, this paper proposes a novel laser shock strategy based on the Leidenfrost effect, wherein suspended droplets are used as the confinement medium. The dynamic behaviors of the droplets during laser shock process were studied. The focusing enhancement effect of the droplets was comprehensively explored. By combining the dynamic behaviors and focusing enhancement effect of the droplets, a theoretical model of the laser shock pressure under droplet confinement was established. Finally, a typical application of the droplet-confined laser shock process in the fields of forming and strengthening was demonstrated to verify its effectiveness and feasibility at high temperatures. The proposed process provides a flexible, convenient, and green plasma confinement strategy that allows stable operation of laser shock at high temperatures. Moreover, the droplet confinement strategy broadens the application prospects of laser shock, and provides a technical support for enabling enhanced ductility and dynamic strain aging of alloys at high temperatures.