Study of machinability of metal matrix composites produced by upward friction stir processing

• Autor(a) principal: Matos, Diogo Alexandre da Silva
• 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/10362/158289
• topic: Metal matrix composites; Milling; Cutting force; Tool wear; Surface quality; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Mecânica

Metal matrix composites (MMC) are materials that have attracted a lot of attention in several industries such as aerospace and automotive due to their excellent mechanical properties. Nowadays, one of the most used process to produce MMC is the Friction Stir Processing (FSP), which modifies the microstructure of the metal and allows the addition of reinforcement particles. Most of these materials require machining operations to obtain the desired shape, size and surface quality. However, machining of MMC is usually associated with high cutting forces, severe tool wear and poor surface quality. In this investigation, MMC were produced via an innovant variant known as Upward Friction Stir Processing (UFSP), by adding SiC particles to the aluminium matrix. Subsequently, several milling operations were performed, where the cutting speed and feed rate were varied in order to analyse the evolution of cutting forces as well as tool wear and surface roughness. Thus, it was possible to have a perception of the most suitable parameters for machining these materials. The results achieved demonstrate that these three indicators are interrelated, and that tool wear is the most critical parameter in the milling of MMC. Additionally, also the particle distribution in the matrix had influence on the results.