Estudo das variáveis do processo de produção de compósito alumínio - quasicristal por extrusão a quente

• Autor(a) principal: Sousa, Fernando Luís Vieira de
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/tede/5358
• topic: Compósito; Quasicristal; Compactação; Extrusão a quente; Composite; Quasicrystal; Compaction; Hot extrusion; CNPQ::ENGENHARIAS::ENGENHARIA MECANICA

The composites metal matrix exhibit properties that are of great interest to the mechanical and aerospace industry, especially when it incorporates low weight with high strength. Currently, the composites ductile matrix reinforced with nanoparticles of amorphous and quasicrystalline alloys have been studied intensively. One reason is that quasicrystals exhibit aperiodic crystal structures, a fact that gives these materials unique properties such as low friction coefficient, high hardness, among others. In these work, the effect of extrusion variables in the production of aluminum composite reinforced with 0%, 3%, 6% and 20% quasicristal Al59,2Cu25,5Fe12,3B3 alloy has been studied. The composites were obtained by mechanical alloying with balls mass ratio 10:1, with rotation of 200rpm, in the period of 3h. The powder mixtures were conformed by hot compaction and extrusion. The analysis carried out by scanning electron microscopy (SEM) showed good distribution of quasicrystalline particles in the aluminum matrix, but was not detected the presence of formation of quasicristal interface with the matrix. It was observed that there was in increases in hardness of the composite increases with the fraction of reinforcement in the matrix, and also with increasing temperature and the rate of extrusion.The maximum resistance to traction was 196MPa, reached with 6% composite reinforcement. It was also found that the tensile strength increases with increasing temperature and mainly by increasing the rate of extrusion. It was found that for the pure aluminum the maximum resistance occurs for the extruded at 450°C. Thus it can be concluded that increasing extrusion temperature of 400°C to 500°C accompanied the increase in extrusion ratio from 2:1 to 3:1 provides improvements in the mechanical properties of the aluminum-quasicristal composite obtained by mechanical alloying and conformal by compaction and extrusion.