The Control of Flow Localization in the Post Severe Plastic Deformation (SPD) Forming of Aluminum Through the Application of Low Strain Amplitude Multidirectional (LSA-MDF) Forging

Severe Plastic Deformation (SPD) of metals leads to their strengthening and losses in the work hardening capacity. The latter causes flow localization upon subsequent forming of the material. The application of Low Strain Amplitude Multi-Directional Forging (LSA-MDF) after SPD regenerates the material work hardening capacity and available results cover 4LSA-MDF cycles after 1 and 4ECAP (Equal Channel Angular Pressing) passes in aluminum; the effect of more LSA-MDF cycles after ECAP is not known. This paper presents results for the application of 8, 12 and 16LSA-MDF cycles after 4ECAP passes in aluminum, which led to further work hardening capacity regeneration of the material. The corresponding microstructural evolution involved an increase and stabilization of the HAGBs fraction and increases in the 5-15º boundary disorientation fraction. Monotonic compression after ECAP+LSA-MDF exhibited almost linear work hardening rates, connected to decreases in the HAGBs fraction and increases in the 2-5º boundary disorientation fraction.

Keywords:
Aluminum; Severe Plastic Deformation; Low Strain Amplitude Multi-Directional Forging; Microstructures; Work hardening