Abstract:The pressure-displacement curves of hot-extruded 6061 aluminium alloy and SiCw/6061Al composites under different forming temperatures were measured to show the difference between these two kinds of materials. Based on the analysis of the forming process, the directionality and breakage of whiskers in hot-extruded tubes and cup-like parts were also investigated. It is shown that, compared with aluminium alloy, the resistant force of deformation of the composite is remarkably higher; and when the back-extrusion in solid state is conducted, the phenomenon of work-hardening appears, but it does not appear when the sample is extruded in liquid-solid region. SiC whiskers tend to break and distribute directionally in extrusion processes
and the degree of breakage and directional distribution is consistent with that of plastic flow of metals.

Key words: SiC whisker　aluminium matrix composite　forming of hot-extrusion