Friction extrusion (FE) is a thermo-mechanical process using a die to produce fully consolidated extrudate in different shapes, i.e. wire and tube. FE uses a non-consumable die to plastically deform material and generates heat by friction between die and base materials. The plasticized material is extruded through the die orifice under extrusion pressure, forming extrudates. No external pre-heating is required during the process, resulting in an energy efficient process.

FE is used successfully to extrude various materials, i.e. aluminum, copper and magnesium alloys, to fabricate extrudates with good properties, such as mechanical behavior and electrical conductivity. Severe plastic deformation and high temperature exposure introduced by the die result in a homogeneous fine-grained structure due to recrystallization. Because the material properties are dependent on their microstructural features, understanding microstructure development during FE is essential.

In the present study, improvement of ductility in aluminum alloys produced by FE and microstructure evolution during the process are discussed. Recrystallization process leading to grain refinement is investigated using an electron backscatter diffraction (EBSD) technique.