Deposition and characterization of AZ61A Magnesium alloy in GMAW-based WAAM

• Autor(a) principal: Neves, José Miguel Lourenço das
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/153191
• topic: WAAM; Magnesium; GMAW; Mechanical properties; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Mecânica

Additive Manufacturing (AM) is considered an integral part of the 4th Industrial Revolu- tion, allowing breakthroughs in each step of production. In this category, Direct Energy Depo- sition processes like Wire and Arc Additive Manufacturing (WAAM) have shown capability of high deposition rates, the ability to produce large parts while being economically advanta- geous. However, many typical defects such as pores and cracks and lack of development with some alloys are still present and require more research. Magnesium alloys are among the least developed alloys for the WAAM process, these alloys can provide a weight reduction of parts produced, which can lead to the reduction of emissions in the transportation sector. This study aimed to successfully deposit the AZ61A Magnesium alloy using an in-house built GMAW-Based WAAM machine. By varying the parameters of the process, the Heat Input (HI) during deposition was affected and its impact on the material was studied. During the project four walled-like samples were deposited, each with its own set of parameters and consequently heat input. First, the Wire Feed Speed (WFS) was established, and other parameters were iterated in accordance with deposition stability and weld bead ap- pearance. The samples had significant internal defects and the process was characterized by deposition instability due to the process instability and material reactivity. The mean grain size was similar between the samples (17.49-22.93 μm). As expected from the similar grain size, microhardness was similar as well with a slight tendency to decrease as HI increased. Tensile testing was only conducted for sample S1 due to internal defects. During this project, several obstacles such as, dissimilar materials, deposition instability, and thermal properties of the Magnesium alloy were detrimental to the successful deposition of samples. Acceptable parameters were obtained, and the resulting properties characterized. To further the application of these alloys in GMAW-Based WAAM, development is needed.