Severe plastic deformation (SPD) techniques have been widely used to enhance strength and promote grain refinement in metals. Multi-Directional Forging (MDF), based on successive compressions with strain path changes, enables tailoring of microstructure and mechanical properties by controlling strain amplitude (Δɛ) and total strain (ɛt). In this study, copper (99.8%) was processed at room temperature using two MDF amplitudes: Δɛ ≈ 0.075 and Δɛ ≈ 0.50 with ɛt between 0.075–3.6 and 0.50–3.0, respectively. Hardening in early compressions is mainly due to dislocation tangles and LAGBs. A higher Δɛ intensifies cross-Bauschinger effects and produces a bimodal microstructure with recrystallized and deformed regions after ɛt ≈ 3.0. The results contribute to understanding how Δɛ and ɛt influence microstructure and strength in copper during MDF.
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