Effect of deep cryogenic treatment on the mechanical properties of AlSi7Mg casting alloy

Abstract. Alloys from the Al-Si system are not hardened by heat treatment and are mainly used for casting lightly stressed parts. If Mg (below 1%) is added to the Al-Si system, the hardening after quenching and aging is possible, as a strengthening secondary phase – Mg2Si – is released. Therefore, the AlSi7Mg alloy is one of the most widely used alloys to produce cast automobile wheels, as well as for thin-walled castings with complex relief. In the present study, the possibilities of extra increasing of the mechanical properties of AlSi7Mg alloy by deep cryogenic treatment were investigated. The tests were carried out on samples of AlSi10Mg alloy previously hardened with T6 heat treatment mode (quenching at 530 ℃ temperature and artificial aging at 170 ºС) and on specimens that have not been hardened by heat treatment.