Forward extrusion of aluminium alloy billet using oil containing fine ceramic particles

Abstract

To increase hardness and to reduce surface roughness of an extruded billet, an oil containing fine ceramic particles was used in extrusion. During extrusion, the fine ceramic particles in the oil flowed into the interface between the billet and die. The some particles were embedded on the billet surface by deformation. The hardness in the surface of extruded billet increased by the embedded particles. The billet surface was polished by the particles in the oil. The hard fine ceramic particles such as SiO2, ZrO2 and Al2O3 having 20 nm to 1000 nm in the particle diameter were used for aluminium alloy A5056 billets. The effects of material, the particle diameter and constituent on the hardness and surface roughness of the extruded billet were investigated. To reduce the surface roughness, the large particle diameter with the high constituent was effective. The hardness of the extruded billet using the oil containing fine ceramic particles was larger than that without the fine ceramic particles. It was found that the use of the oil containing the fine ceramic particles is effective in hardening and reducing the surface roughness of the extruded billet.