Londiwe Motibane

Effect of Increased Powder Pre-Heating on Microstructural Evolution, Distortion caused by Residual Stress and Mechanical properties
Due to the high cooling rates and thermal gradients inherent in SLM processing, residual stresses can occur in as-built components. These residual stresses have been shown to have a significant influence on crack growth behaviour and deformation.The final component is not always ready to be used as it can fail prematurely later in service. Post-heat treatments are available avenues to relieve these stresses, but imply longer processing time and additional cost. Preheating of the powder can be used to reduce these stresses because it lowers thermal gradients. The research will investigate the effect of powder preheating on the microstructure of the components, the distortion caused by residual stresses and also the resulting mechanical properties. The test parts will be built using the Aeroswift high speed SLM machine. The Aeroswift is a result of collaboration between CSIR National Laser Center, Aerosud Aviation and the Department of Science and Technology.