Textures in powder-metallurgy processed Nb/Al composites

The powder metallurgy process, including hot extrusion and cold rolling, was used to fabricate an Nb/Al metal-metal composite plate. The crystallographic textures in matrix Al and reinforcement Nb were separately studied by an ODF and pole figures analysis at stages of hot extrusion, cold-rolling and subsequent annealing. As hot extruded state, the texture in the Al matrix is nearly random distributed and can be represented by a weak fiber of left angle 111 right angle, while the reinforcement Nb of the composite forms a moderate left angle 100 right angle -fiber and {001} left angle 110 right angle component. The matrix Al forms the typical f.c.c. rolling texture or β-fiber after cold-rolling process, and it becomes stronger with increasing cold rolling reduction. Meanwhile, the left angle 100 right angle -fiber and {001} left angle 110 right angle textures remained in reinforcement Nb after cold rolling process. The results also show that there formed a strong {100} recrystallization texture in the Al matrix after annealing but the fiber texture of the reinforcement Nb has little weakening tendency and shows fiber texture invariant. The high strength of such a kind of metal-metal composite can be explained in terms of the unusual orientation relation of the reinforcement before and after annealing. (orig.)