INVESTIGATION OF THE EFFECT OF THE PRINTING PARAMETERS ON THE MECHANICAL PROPERTIES OF SLM PRINTED PARTS

Abstract

This Thesis work is written about how printing parameters and heat treatment can influence the resultant properties of additively manufactured components. The additive manufacturing method used is selective laser melting, which has gained increased attention from researchers due to the opportunities it can offer in biomedical, aerospace, automobile, and other industries. However, the SLM-ed parts can be flawed due to various defects such as porosities. Moreover, residual stresses also contribute to the parts’ performance deterioration. There is still a lack of understanding of the connections between printing parameters, mechanical properties, and post-processing influence. Hence, this work aims to test and analyze the samples printed using AlSi10Mg powder. It was proposed to use a design of experiments to evaluate the effects of both process parameters and heat treatment. It was found that platform heating and consequent stress relief heat treatment can considerably weaken the SLM-ed AlSi10Mg samples. Also, it was found that horizontally printed samples are the weakest in terms of ultimate tensile strength. Moreover, as-built samples printed at 0﮿ had a poor performance during fatigue testing. A possible explanation could be the presence of residual stresses. In conclusion, though the studies indicate that as-built samples are stronger than heat-treated samples both in terms of tensile strength and fatigue resistance due to fine microstructure, residual stresses that are induced during printing can cancel the effect of fine microstructure.