On the other hand, for the purpose of improving formability and
toughness of Al–Mg alloy, chemical composition of the AlMgxSi2Mn
alloy applied in this work possesses several characterizations
as follow: (1) weight fraction of impurities and Cu are
reduced to a low level (60.05%). (2) Fe content is reduced to as
low as 0.15% to avoid its negative effect. (3) Addition of Si (2%)
and Mn (0.5%) are employed to facilitate die casting process
through by means of improving the formability and decreasing
die soldering tendency. In fact, the microstructure formation of
HPDC AlMg5Si2Mn alloys had been studied by Otarawanna [7].
However, the accurate phase composition and relationship between
the heat treatments and mechanical properties of that alloy
need to be confirmed by a further research.
Heat treatments to die casting aluminum alloys were seldom
studied since high temperature triggers severe gas expansion and
irreversible dimensional variations [8,9], both of which are unacceptable
for die casting products. Brungs [8] studied the property
improvement of die casting AA360 alloy subjected to energyconsuming
T6 treatment. Therefore, searching a cost-efficient and
energy-saving method to avoid those negative effects and improve
mechanical properties of AlMgxSi2Mn die casting is necessary. In
addition, the optimized aging temperature and time were chosen
(250 C/1 h) to shorten the test cycle.
Fatigue properties of various aluminum alloys were widely
investigated. For example, Ammar et al. [10–12] investigated
the fatigue behavior of die casting Al–Si (A356, etc.) and
Al–10%Si–2%Cu alloys and emphasized the negative effects of
surface defect and Fe. Moreover, Boyapati and Polmear [13]