Abstract
δ-Al2O3/Al composites were fabricated by high pressure infiltration and extruded at high temperatures. The plastic flow in extruded matrices is classified into two types, namely a laminar flow in the surface region and a turbulent flow in the core. The wider the laminar flow region, the better the fiber alignment obtained. The laminer flow region extends at lower Vf and lower extruding temperatures. Surface defects, fir-tree-type cracks, easily grow at high Vf. The δ-Al2O3/Al alloy has tensile strength twice as much as that the matrix alloy extruded in the same way.
