Phase-field simulation and high-temperature confocal laser scanning microscope experimental study of Martensite transformation during the disk laser quenching process

Abstract

Laser quenching has significant advantages over conventional heat treatment. The main microstructure of C30E4 steel after quenching at a specific temperature is Martensite. Accurately obtaining the microscopic characteristics of the Martensite transformation process is the key to obtaining the best material properties, which is significant to material design. In this paper, the C30E4 steel was disk-laser-quenched, the metallographic and high-temperature confocal laser scanning microscope experiment was carried out. The microstructure of the fully phase-change hardened zone, heat-affected transition zone and matrix zone after quenching was obtained. The C30E4 martensitic transformation process in-situ was obtained. The mathematical physics model of Martensite transformation from metastable to steady state was established by phase field method. The finite-element method was used to solve the model, and the quenching Martensite transformation law was obtained. The Martensite formation process in austenite grain boundaries and microstructure defects was discussed. The experimental and the numerical simulation were compared to get consistent results, which verify the validity of the calculation method. This study lays a significant foundation for effectively revealing the Martensite formation and transformation during the disk laser quenching process, and provides a theoretical basis for quantifying the influence of Martensite transformation process on material properties.