Tailoring the composition of 2017 aluminum alloy to reduce its crack susceptibility during selective laser melting

Abstract

Aluminum alloys are one of the most important metallic materials used nowadays due to their low density and excellent mechanical properties, making them attractive to be applied in additive manufacturing processes such as Selective Laser Melting (SLM). However, the high thermal gradients generated in SLM favors the formation of hot cracks, which deteriorated the mechanical behavior of the built parts. Due to this, few are the aluminum alloys that have been successfully commercially processed by SLM, highlighting the Al-Si and Al-Si-Mg alloys as a cause of their short solidification interval. On the other hand, wrought aluminum alloys, e.g. Al-Cu based alloys (2xxx series), have a large solidification interval which favors their susceptibility to cracking. Therefore, the composition of several of these alloys has to be modified to be processable by SLM. In this context, the purpose of this work is focused on modifying the composition of AA2017 to reduce the formation of cracks during SLM. Subsequently, the microstructure and mechanical properties of the SLM samples will be studied. However, the DEMa/UFSCar does not have an SLM machine capable to produce large samples of the modified AA2017 parts for the mechanical tests, in addition to other equipment and techniques that may allow a better characterization of the parts produced. The present BEPE FAPESP project will allow the student to have access to the SLM machine available at the Graz University of Technology - TU Graz, Austria, in addition to other equipment such as X-ray microcomputed tomography (µCT) that allows determining the fraction and distribution of pores in SLM samples. The large experience of the TU Graz research group in the area of characterization and additive manufacturing of aluminum alloys will certainly give a great contribution to the development of this doctoral work. The student planned to stay one year in Austria at the TU Graz to build different samples by SLM and carry out part of the microstructural and mechanical characterization. (AU)