Factors Affecting Toughness and Corrosion Resistance of AA6082 Forgings

Abstract

AA6082 extruded bars were annealed and then hot-deformed at 693 K, cold-deformed at room temperature (RF), or treated at sub-zero temperatures (CF). After the solution and the aging treatment, the mechanical properties of the samples were tested. The experimental results demonstrate that the hot-deformed samples were stronger but less elongated than the RF and CF samples. All hot-deformed (HF), RF, and CF samples had mechanical properties that exceeded UTS > 310, YS > 260 MPa and an elongation > 10%. The RF and CF samples greatly enhance elongation (up to 16%) and toughness in addition to moderate strength (UTS ≥ 320 and YS ≥ 295 MPa). Affected by having high fractions of high misorientation angle grain boundaries (MAGBs) per unit area in the matrix, the RF and CF samples deteriorated their corrosion resistance by degrading Ecorr values. The surface of corroded HF50 was recorded to confirm that the particles were attacked by chloride and oxidized. Increasing the total lengths of high-MAGBs and particle counts per unit area accelerated corrosion to lift up Icorr values.