ON THE MECHANISM OF CREEP IN SHORT-FIBER-REINFORCED ALUMINUM-ALLOYS

The present work studies creep damage accumulation in a squeeze cast, short fibre reinforced aluminium alloy containing 15 vol.% of Saffil f ibres. Fibre breakage occurs early in creep life. Individual fibres ca n undergo more than one rupture event. Primary and tertiary creep are closely related processes and cannot be considered as being independen t. The minimum creep rate is a result of a superposition of load trans fer from the matrix to the fibres (decrease of creep rate) and fibre b reakage (increase of creep rate). In summary, creep of short fibre rei nforced aluminium alloys is governed by three elementary processes inc luding (i) loading of fibres through the formation of a work hardened zone around the fibres, (ii) a recovery mechanism in the work hardened zone, and (iii) the breakage of fibres into subfibres.