Study of nanostructural defects in Metal Matrix Al-Cu Composites by positron annihilation spectroscopy

W.SALGUEIRO, O.GARBELLINI, C.MORANDO, A.SOMOZA AND H.PALACIO

Buenos Aires, Argentina

Congreso; COMAT 2005, International Conference on Science and Technology of Composite Materials; 2005

The field of metallic matrix composites (MMCs) has become of paramount importance in the field of materials science. This kind of materials shows some advantages on the physical and mechanical properties when compared with conventional metallic materials, specifically in high temperatures applications. With respect to metals and alloys, MMCs show a better response to abrasion, fatigue, corrosion and oxidation, less density and thermal conductivity, higher hardness, specific modulus and service temperatures. Furthermore, they show a small thermal expansion coefficient. Such attributes are very useful in a broad range of structural and electronic applications. These materials are subject of intensive research effort. The detailed microstructural mechanisms responsible for the macroscopic properties are not yet well understood. Specifically, the accumulation damage mechanisms are open to research and there is some controversy in the literature. In this scenario, the aim of the present work is to gain information on the point-like defects and porosity developed during the composites fabrication. To this scope, MMCs were fabricated and, then, studied using positron lifetime annihilation spectroscopy (PALS). This experimental technique is broadly used in the study of point-like defects, nanostructures and nanoporosities in metals, alloys, polymers and composites. For more details about PALS technique see ref. (2).