Heat transfer in metallic glasses during laser cutting

Laser cutting of thin, brittle materials requires a thorough understanding of the thermal effects occurring at the laser interaction zone to prevent cracking and other undersirable heating effects. An investigation was undertaken to determine the parameters of importance in laser cutting of metallic glass ribbons which undergo ductile-to-brittle phase transitions when heated above crystallization temperatures. The laser/material interaction was modeled using a quasi-steady, three-dimensional finite-difference technique to predict the temperatures and cooling rates in the heat-affected zone. The model was created to achieve proper material removal, to account for the energy lost through the kerf, and to predict the temperature field in the material adjacent to the cut (heat-affected zone). The thermal stress field in the material was calculated based on the calculated temperatures. The predictions obtained from the model were compared with experimental cutting data.