A novel cyclic forward-backward extrusion process for production of ultrafine grains materials

H. Alihosseini, M. Asle Zaeem, K. Dehghani
Mississippi State Univeristy, US

Keywords: severe plastic deformation, aluminum alloy, ultrafine grained rods, mechanical properties, TEM, EBSD

Summary:

A new cyclic forward-backward extrusion (CFBE) process was introduced as a severe plastic deformation (SPD) technique to produce ultrafine-grained aluminum rods. According to transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) results, the average grain size was reduced from 120μm to 315 nm after only three cycles of CFBE. Yield strength and tensile strength of the specimens increased by increasing the number of CFBE cycles, while elongation to break decreased due to an increase in the grain refinement and microhardness. Compared to conventional SPD techniques, the structure produced by CFBE was more homogenous, containing nearly equiaxed grains.