Creep of metal matrix composites reinforced by combining nano-sized dispersoids with micro-sized ceramic particulates or whiskers (review)

The micro-sized ceramic whiskers or particulates can greatly increase the specific modulus and other mechanical properties of aluminium alloys. However, the strength at high temperatures depends on microstructures of the matrix. The nano-sized fine dispersoids can markedly increase the high temperature strength of aluminium alloys, but elastic modulus of these dispersion-strengthened alloys is not significantly improved. Therefore, a new kind of metal matrix composite reinforced by combining nano-sized dispersoids with micro-sized ceramic whisker- or particulate-reinforcements, has been developed. This paper presents the experimental results and analysis on the effects of micro-sized ceramic whiskers or particulates on creep strain rates in the composites by taking account into the load transfer model from matrix to reinforcements. In particular, comparison of creep behaviour between titanium and aluminium matrix composites is conducted. Technological barriers and trends associated with practical utilisation, development and research of metal matrix composites are also addressed.