Simultaneously enhancing the tensile properties and intergranular corrosion resistance of Al-Mg-Si-Cu alloys by a thermo-mechanical treatment

A novel thermo-mechanical treatment consisting of conventional pre-aging, cold-rolling and re-aging was developed to enhance the tensile properties and intergranular corrosion resistance of Al-Mg-Si-Cu alloys simultaneously. The thermo-mechanically treated 6061 Al sheets exhibit higher ultimate tensile strength and yield strength (being 466 MPa and 451 MPa) than those of the conventionally peak-aged alloys (being 365 MPa and 347 MPa), and meanwhile have no intergranular corrosion susceptibility and good elongation of 8.1%. Based on the microstructure evolution during the thermo-mechanical treatment, the factors that enhance the tensile properties and intergranular corrosion resistance of the treated sheets are discussed in detail.