The load transfer effect in the true threshold creep behaviour of an Al-8.5Fe-1.3V-1.7Si alloy reinforced with alumina short fibres

The creep in an Al-8.5Fe-1.3V-1.7Si alloy dispersion strengthened with fine Al-12(Fe,V)(3)Si phase particles and reinforced with alumina short fibres - Composite in the following - is investigated at temperatures 648, 698 and 748 K. The results are compared with those obtained for the composite matrix Al-8.5Fe-1.3V-1.7Si alloy ( Alloy in the following) at the same temperatures. Both, the Alloy and the Composite exhibit true threshold creep behaviour; the true threshold stress decreases rather strongly with increasing temperature. However, independently of temperature, it is about twice as high in the Composite than in the Alloy. This is explained employing the concept of the load transfer effect in the true threshold creep behaviour. The results strongly suggest that rather dramatic enhancement of creep resistance of an Al-8.5Fe-1.3V-1.7Si alloy can be reached introducing into it mechanically strong short fibres of micrometer dimensions, provided the aspect ratio of the fibres and their volume fraction are large enough. (C) 2003 Kluwer Academic Publishers.