To improve the wear resistance of cast Al?17Si?5Cu alloy(AR alloy),isothermal heat treatment is employed to modify the morphology of Si particles(particularly eutectic Si particles).Furthermore,wear behaviour of heat-...To improve the wear resistance of cast Al?17Si?5Cu alloy(AR alloy),isothermal heat treatment is employed to modify the morphology of Si particles(particularly eutectic Si particles).Furthermore,wear behaviour of heat-treated alloy(HT alloy)along with AR alloy is studied using a pin-on-disc tribometer.Worn surfaces are then characterised using scanning electron microscope.The result reveals considerable microstructural modifications after the heat treatment.Accordingly,higher hardness value in HT alloy is obtained compared with AR alloy.The overall wear rate for HT alloy is found to be significantly lower compared with AR alloy at all the applied loads,indicating remarkable improvement in wear resistance.Eutectic Si particles become from acicular/rod-like to spherical/equiaxed morphology(aspect ratio close to 1)on heat treatment,resulting in good bonding with the matrix.Thus,they remain intact during wear and being harder,providing resistance to wear.Moreover,the increased hardness on heat treatment causes further resistance to wear.Therefore,the combined effect of intact harder Si particles on the wearing surface and higher hardness results in superior wear behavior in HT alloy at all loads compared with AR alloy.展开更多
The goal of the present study is to improve the elevated temperature wear resistance of an Al-17 wt%Si-5 wt%Cu alloy(AR alloy) by a novel short duration heat treatment process. The elevated temperature(100°C) dry...The goal of the present study is to improve the elevated temperature wear resistance of an Al-17 wt%Si-5 wt%Cu alloy(AR alloy) by a novel short duration heat treatment process. The elevated temperature(100°C) dry sliding wear behavior of an AR alloy was studied after microstructural modification using the proposed heat treatment. The study revealed considerable microstructural modifications after the heat treatment and the heat treated alloy was designated as HT(heat treatment) alloy. A higher hardness value was obtained for the HT alloy compared to the AR alloy. Accordingly, the wear rate for the HT alloy was found to be significantly lower compared to the as-cast AR alloy at all applied loads. Accelerated particle pull-out for the AR alloy at elevated temperatures resulted in poor wear behavior for it compared to the HT alloy. On the other hand, the Si particles remained intact on the worn surface of the HT alloy due to the good particle/matrix bonding that resulted from the isothermal heat treatment. Furthermore, the age hardening that occurred in the HT alloy during wear provided additional wear resistance. Thus, the HT alloy at 100°C exhibited a lower wear rate compared to the AR alloy even at room temperature for all applied loads. This improvement was attributed to microstructural modification upon isothermal heat treatment along with the age hardening effect.展开更多
基金DST-SERB grant, vide Project No. YSS/2014/000172 dated 2015-08-17
文摘To improve the wear resistance of cast Al?17Si?5Cu alloy(AR alloy),isothermal heat treatment is employed to modify the morphology of Si particles(particularly eutectic Si particles).Furthermore,wear behaviour of heat-treated alloy(HT alloy)along with AR alloy is studied using a pin-on-disc tribometer.Worn surfaces are then characterised using scanning electron microscope.The result reveals considerable microstructural modifications after the heat treatment.Accordingly,higher hardness value in HT alloy is obtained compared with AR alloy.The overall wear rate for HT alloy is found to be significantly lower compared with AR alloy at all the applied loads,indicating remarkable improvement in wear resistance.Eutectic Si particles become from acicular/rod-like to spherical/equiaxed morphology(aspect ratio close to 1)on heat treatment,resulting in good bonding with the matrix.Thus,they remain intact during wear and being harder,providing resistance to wear.Moreover,the increased hardness on heat treatment causes further resistance to wear.Therefore,the combined effect of intact harder Si particles on the wearing surface and higher hardness results in superior wear behavior in HT alloy at all loads compared with AR alloy.
基金financially supported by Department of Science and Technology (India), G.O.I (No. YSS/2014/000172)
文摘The goal of the present study is to improve the elevated temperature wear resistance of an Al-17 wt%Si-5 wt%Cu alloy(AR alloy) by a novel short duration heat treatment process. The elevated temperature(100°C) dry sliding wear behavior of an AR alloy was studied after microstructural modification using the proposed heat treatment. The study revealed considerable microstructural modifications after the heat treatment and the heat treated alloy was designated as HT(heat treatment) alloy. A higher hardness value was obtained for the HT alloy compared to the AR alloy. Accordingly, the wear rate for the HT alloy was found to be significantly lower compared to the as-cast AR alloy at all applied loads. Accelerated particle pull-out for the AR alloy at elevated temperatures resulted in poor wear behavior for it compared to the HT alloy. On the other hand, the Si particles remained intact on the worn surface of the HT alloy due to the good particle/matrix bonding that resulted from the isothermal heat treatment. Furthermore, the age hardening that occurred in the HT alloy during wear provided additional wear resistance. Thus, the HT alloy at 100°C exhibited a lower wear rate compared to the AR alloy even at room temperature for all applied loads. This improvement was attributed to microstructural modification upon isothermal heat treatment along with the age hardening effect.
