Effect of laser heat treatment on microstructure of magnesium alloy

• Main Author: Ong, Yu Qi
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/60979
• Institution: Nanyang Technological University

Use of Magnesium alloys in biomedical applications has been increasing throughout the years and much research and development had been done to improve the corrosion properties of the alloys. One of the more promising way is to make use of laser heat treatment to change the microstructure of the magnesium alloy in a bid to improve its corrosion resistance. In this project, a simulation software (COMSOL Multiphysics) is used to develop a model to investigate the process of heat transfer and resultant temperature profile induced by the laser beam. It was found that the temperature profile is affected by a number of factors like power density, scanning speed, laser spot size, thickness and size of material, reflectance and absorption coefficient and line density. The simulation model is a good avenue to test the parameters to be input into the laser experiment, as the user will know whether melting or ablation (microstructural phase change) will be involved when doing the experiment. Experiments were also conducted using the parameters from simulation. The results obtained from experiments were not conclusive as it was found that the absorption coefficient differs from the settings in the simulation due to the surface smoothness of specimens after grinding and polishing. However, with these temperature profile results and simulation model, future works can be done to model the microstructural change with the temperature induced by the laser beam.