Effect of pre-aging treatment on mechanical properties and precipitation of 6016 alloy

The effects of pre-aging treatment on the mechanical properties and the precipitation behavior of 6016 alloy were studied by means of first-principles calculations, hardness tests, tensile tests, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Studies show that pre-aging treatment can inhibit the negative effects of natural aging. What′s more, pre-aging treatment of 110 ℃ × 10 min can significantly inhibit the natural aging and maintained good formability (σ_0.2: 109.65 MPa) of sheet; Pre-aging can improve paint baking response and pre-aging treatment of 110 ℃ × 10 min showed the best paint bake performance (σ_0.2: 212.29 MPa). But paint baking response decreased with the increase of pre-aging time and temperature; Different pre-aging treatment didn′t change the composition of the phases in the matrix which mainly were α-Al and Mg₂Si.In addition, the Mg₂Si phase increased slightly with the increase of time and temperature; More needle-like β" phases precipitated and the mechanical properties were better after paint baking treatment with the pre-aged treatment sample, which was in accordance with the physicochemical properties of the β sequence calculated by the first-principle calculation.