Controlling the microstructure and strength of copper submitted to multidirectional forging

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 (Δ ɛ ) and total strain ( ɛ t ). In this study, copper (99.8%) was processed at room temperature using two MDF amplitudes: Δ ɛ ≈ 0.075 and Δ ɛ ≈ 0.50 with ɛ t 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 Δ ɛ intensifies cross-Bauschinger effects and produces a bimodal microstructure with recrystallized and deformed regions after ɛ t ≈ 3.0. The results contribute to understanding how Δ ɛ and ɛ t influence microstructure and strength in copper during MDF.