Low temperature extrusion of 6061 aluminum matrix composite reinforced with SnO2-coated Al18B4O33 whisker

The 6061 aluminum matrix composite reinforced with SnO2-coated Al18B4O33 whisker was fabricated by squeeze casting and following by extrusion extruded at elevated temperatures from 300 degrees C to 400 degrees C. Optimization of the extruding process, microstructure, texture and mechanical properties of the extruded composites were investigated. The lowest extrusion temperature at which a composite rod with high surface quality was successfully produced was 300 degrees C. The yield strength of composites is much improved after extrusion, and especially their elongation is increased by 300%. Such big improvements depend on a fact that SnO2 coating can introduce low-melting-point Sn phase into the interface through an interfacial reaction. The melting of interphase and their surrounding areas is the main reason for the excellent extrusion ability of the composite. Besides, detailed X-ray diffraction analysis of the extruded composite textures reveals the significant effects of extrusion temperatures on their features. (C) 2011 Elsevier Ltd. All rights reserved.