Abstract

The thermal effects of fibre laser surface treatment on a Si3N4 engineering ceramic were studied using a computational finite element analysis (FEA). Temperature increases on the surface of the Si3N4 during fibre laser processing were measured using an infra-red thermometer; temperature distributions in the bulk were measured with specifically located thermocouples. A computational model by using FEA was then developed to model the flow and the distribution of the radiated heat resulting from the fibre laser treatment of the Si3N4 ceramic. By utilising data obtained from a TG-DSC analysis the FEA model predictions of the temperature distribution were used to map phase transformations and significant events occurring during the fibre laser surface treatment of the Si3N4. The TG-DSC analysis also indicated that the fibre laser surface treatment generally resulted in a phase transformation of the Si3N4 from α-phase to β-phase modification as elongated rod-like grains were found.