Aluminium based metal matrix composites for improved elevated temperature performance

Abstract

The thermal performance of six commercially available particulate reinforced metal matrix composites (MMCs) has been investigated, including the effects of continuous thermal exposure and thermal cycling on ambient and elevated temperature tensile properties, toughness, and fatigue. Additionally, accelerated creep tests and thermal cycling tests under load were carried out. Some aspects of the performance of these MMCs were very promising, particularly strength up to 200°C and good retained strength after extended exposure at up to 260°C, while resistance to creep and thermal cycling under load was generally not as good. The results were used as a basisfor selected tests on some development MMCs aimed at improvements to particular aspects of thermal performance. The use of 2618 type aluminium alloys as a matrix for powder route SiC reinforced MMCs, in place of 2124, had no significant effect, but initial results suggest that the use of ultrafine oxides as reinforcement in aluminium alloys may improve strength above 200°C.