Desenvolvimento do compÃsito Al-5,0Si-1,0Cu/Al203 CaracterizaÃÃo microestrutural e trabalhabilidade

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The development of the metal matrix composites (MMC) is considered one of the major innovations of materials in the last thirty years. These new materials are receiving great attention of the researchers in the entire world for diverse industrial applications because of their high mechanical strength, much superior than non-reinforced alloys. The factors that still limit the utilization of these materials are compatibility of matrix and reinforcement and high production cost relative to the mode of reinforcement. In the present work of dissertation, equipments have been developed which make it possible to elaborate composite materials based on alumina matrix by the process of rheocasting. Two machines were fabricated: one for incorporation of reinforcement by mechanical agitation of melted alloy and other one for compactation using a vibratory table with a support for the solidification mould. Using these equipments aluminum metal matrix (Al-5,0Si-1,0Cu) reinforced with 1, 2 and 4% of alumina (Al2O3)were developed. These materials were produced by conventional casting process with the incorporation of reinforcement under mechanical agitation (Stirring cast) and pouring the reinforced alloy in semi-solid state (rheocasting). After elaboration of composites, these materials microestrutural characterization were carried out by optical microscopy. Tests of workability, shaping and machining were realized to evaluate the possibility of fabrication of parts and structural components, keeping in view utilization of these type of materials for industries in general. For the shaping tests material was heated at a temperature of 515oC using a muffle type furnace and after this it was deformed in a goldsmith type roller with a deformation rate of 1.6 s-1 and reduction (Dh) by constant pass. The machining test was carried out in a mechanical lathe machine using computer numerical control (CNC). Considering the incorporated tenor of alumina, machinebility was evaluated in terms of the surface finishing (roughness). Results show that the process of rheocasting became successful and incorporated reinforcement was distributed in entire matrix principally in grain boundaries. It is possible to confirm that these materials retain their structural integrity up to 10% on heating. In the machining, the predominant mechanism, of the consuming of the cut tool, was the abrasion with formation of detachable edge, but it revealed that it is possible to produce mechanical parts for this process of manufacture. The composites with aluminum matrix strengthened with fine alumina particles (Al2O3) had revealed very promising for industrial application, since that the size and the morphology (amount and dispersion) of the reinforcement in the matrix is controlled

ASSUNTO(S)

compÃsitos com matriz metÃlica de alumÃnio matriz metÃlica de alumÃnio engenharia mecanica aluminum metal matrix metal matrix composites

ACESSO AO ARTIGO

Documentos Relacionados