Age-hardening behavior of al-10%si-0.3%Mg alloy with water quenching and direct quenching after solution treatment

Age-hardening behavior of Al-10 mass%Si-0.3 mass%Mg alloys was investigated using Micro-Vickers hardness measurement and transmission electron microscopy (TEM). The alloys were cast by a permanent mold process, homogenized at 813 K for 36 ks, cold rolled up to 68%, solution treated at 813 K for 36 ks, and then finally artificially aged at 348-523 K after water-quenched (W.Q.) or direct-quenched into an oil-bath at 348-523 K for artificial aging (D.Q.). When the final aging temperature was lower than at 373 K, the hardness at peak aging was not different between W.Q. and D.Q. conditions. However, the final aging temperature was higher than 373 K, the hardness at peak aging for the D.Q. condition was lower that for the W.Q. condition. This is due to the difference of formation such as G.P. zones and/or clusters between W.Q. and D.Q. conditions over 373 K.