High-temperature age-hardening behavior of Al–Mg–Si alloys with varying Sn contents
Gang Lu, Bo Sun, Jianjun Wang, Yujie Liu, Chunming Liu
Abstract
The effects of Sn content on the age-hardening behavior and peak aging precipitates of Al–Mg–Si alloys at 250 °C were investigated by hardness testing, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The results indicated that the peak hardness of the experimental alloys initially increased and then decreased with Sn content increasing from 0 to 0.15 wt.%, and it reached a maximum value of 108 HV in the alloy containing 0.1 wt.% Sn. All the Sn-added alloys exhibited higher peak hardness than the Sn-free alloy. Microstructure observations revealed that the enhanced peak hardness of the Sn-added alloys derived from the refinement of precipitates and their increase in number density. The underlying mechanisms of varying Sn addition contents on the precipitate microstructure were discussed.