| dc.description.abstract | The effect of Sb modification, solution and aging treatment on the microstructure, mechanical properties and anti-wear properties of 4Y32（Al-11.2Si-3Cu-0.5Mg-0.5Mn）aluminum alloy was demonstrated by Optical Microscopy（OM）, Differential Scanning Calorimeter（DSC）,and Scanning Electron Microscopy（SEM）. The results showed that Sb-modified alloy presented a fine lamellar eutectic microstructure. After homogenization, the eutectic silicon undergoes refinement and spheroidization, and hot-rolling caused eutectic silicon undergoes more significant refinement and spheroidization. The eutectic silicon coarsens with increasing solid solution time. After 505℃*0.5hr solution treatment and water quenching, the strengthened solid solution atoms of the alloy can be fully dissolved into the α-Al matrix. The element Sb will not affect the precipitation kinetics or precipitation quantity of the alloy, but the addition of Sb can be refined eutectic silicon of T6 alloy.
Through the addition of modifier (Sb) and solution aging treatments, the morphology and hardness of eutectic silicon of 4Y32 aluminum alloy can be modified. When the hardness of the alloy is same, the eutectic silicon becomes thinner and more resistant to wear. When the size of eutectic silicon is same, the higher the hardness of the alloy, the more resistant it is to wear. Combined with the Sb-modifier, reduction of solution time, and peak aging (T6) heat treatment, the finest eutectic silicon and the highest alloy hardness can be obtained, which will increase the wear resistance of 4Y32 aluminum alloy. During the wear process, a protective oxide layer which is called Mechanical Mixed Layer (MML) is formed on the surface of the alloy. The Sb modified alloy has higher stability, and the stability of the MML decreases with increasing thickness. When the MML peels off due to crack growth and transmission, the wear mechanism is changed from abrasive wear to delamination wear. | en_US |