The combined effect of pre-aging and Sn addition on age hardening response and precipitation behavior of Al-1.0Mg-0.6Si (−0.3Cu) alloy

Abstract

The combined effect of Sn and pre-aging on hardening and precipitation behavior of Al-1.0Mg-0.6Si(-0.3Cu) alloy was investigated by using hardness measurement, tensile test, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicated that the natural aging (NA) hardening of Al-1.0Mg-0.6Si (−0.3Cu) alloy was suppressed by pre-aging treatment, and the suppression of NA can be enhanced by the addition of Cu. However, the suppression of NA time of Al-1.0Mg-0.6Si and Al-1.0Mg-0.6Si-0.3Cu alloy, i.e., without obvious hardness increase after pre-aging treatment, is reduced to 5 and 7 days by the addition of Sn, which is not conducive to the suppression of NA. For subsequent artificial aging (AA) of the Al-1.0Mg-0.6Si (−0.3Cu) alloys, the AA precipitation of Al-1.0Mg-0.6Si alloy with pre-aging treatment is accelerated by the addition of Sn or Cu, particularly by adding both Sn and Cu, resulting in the increase in the bake hardening response. The effect of the evolution of clusters after pre-aging on underling mechanisms of NA and its AA were also discussed.

Keywords

• Sn addition
• Natural aging
• Artificial aging
• Pre-aging
• Precipitation