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
The effects of conform continuous extrusion and subsequent heat treatment on the mechanical and wear-resistance properties of high-alloying Al–13Si–7.5Cu–1Mg alloy were investigated.The microstructures of alloys be...The effects of conform continuous extrusion and subsequent heat treatment on the mechanical and wear-resistance properties of high-alloying Al–13Si–7.5Cu–1Mg alloy were investigated.The microstructures of alloys before and after conform processing and aging were compared by transmission electron microscopy and scanning electron microscopy,respectively.The results reveal that the primary phases were broken and refined by intense shear deformation during conform processing.After the conform-prepared Al–13Si–7.5Cu–1Mg alloy was subjected to solid-solution treatment at 494℃for 1.5 h and aging at 180℃for 4 h,its hardness improved from HBS 115.8 to HBS 152.5 and its ultimate tensile strength increased from 112.6 to 486.8 MPa.Its wear resistance was also enhanced.The factors leading to the enhanced strength,hardness,and wear resistance of the alloy were discussed in detail.展开更多
The influence of heat treatment（T6） on the ambient temperature dry sliding wear behavior of the extruded AZ91 alloy treated with Y using a pin-on-disc apparatus was investigated. Wear rates and friction coefficients...The influence of heat treatment（T6） on the ambient temperature dry sliding wear behavior of the extruded AZ91 alloy treated with Y using a pin-on-disc apparatus was investigated. Wear rates and friction coefficients were measured within a load range of 5-70 N at a sliding speed of 0.188 m/s over a constant sliding distance of 226.195 m. Worn surfaces and debris were examined using a scanning electron microscope equipped with an energy dispersive spectrometer. The experimental results revealed that, as applied load was increased, the alloy wear rates increased, but the friction coefficients decreased. Four chief operating wear mechanisms were observed, i.e., abrasion, oxidation, delamination and plastic deformation. The extruded AZ91 alloy treated with Y exhibited better wear resistance by adopting T6, which was mainly due to large amounts of fine Mg_（17）Al_（12） distributed in the grains and the resulting modified strength and micro-hardness.展开更多
The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kin...The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kind of roller material, the high-vanadium alloy steel （HVAS）, was investigated. The results showed that the as-cast microstructures of the HVAS roller contained martensite, residual austenite, and alloy carbides. The HVAS sample quenched at 1,080 ℃ had a high hardness, and it had much higher compressive strength and abrasive wear resistance after tempering at 560 ℃ for 30 rain. The mechanical properties of the HVAS are more sufficient than the existing roller materials, which are feasible for larger machine design.展开更多
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.
基金financially supported by the National Natural Science Foundation of China (No.51274245)
文摘The effects of conform continuous extrusion and subsequent heat treatment on the mechanical and wear-resistance properties of high-alloying Al–13Si–7.5Cu–1Mg alloy were investigated.The microstructures of alloys before and after conform processing and aging were compared by transmission electron microscopy and scanning electron microscopy,respectively.The results reveal that the primary phases were broken and refined by intense shear deformation during conform processing.After the conform-prepared Al–13Si–7.5Cu–1Mg alloy was subjected to solid-solution treatment at 494℃for 1.5 h and aging at 180℃for 4 h,its hardness improved from HBS 115.8 to HBS 152.5 and its ultimate tensile strength increased from 112.6 to 486.8 MPa.Its wear resistance was also enhanced.The factors leading to the enhanced strength,hardness,and wear resistance of the alloy were discussed in detail.
基金supported by the National Natural Science Foundation of China(51364035)
文摘The influence of heat treatment（T6） on the ambient temperature dry sliding wear behavior of the extruded AZ91 alloy treated with Y using a pin-on-disc apparatus was investigated. Wear rates and friction coefficients were measured within a load range of 5-70 N at a sliding speed of 0.188 m/s over a constant sliding distance of 226.195 m. Worn surfaces and debris were examined using a scanning electron microscope equipped with an energy dispersive spectrometer. The experimental results revealed that, as applied load was increased, the alloy wear rates increased, but the friction coefficients decreased. Four chief operating wear mechanisms were observed, i.e., abrasion, oxidation, delamination and plastic deformation. The extruded AZ91 alloy treated with Y exhibited better wear resistance by adopting T6, which was mainly due to large amounts of fine Mg_（17）Al_（12） distributed in the grains and the resulting modified strength and micro-hardness.
基金supported by the National High Technology Research and Development Program (No. 2012AA03A508)Project of Science and Technology Plan of Shenyang City (No. F12-027-2-00)Project of Science and Technology Plan of Liaoning Province (No. LNSBQ4-2010921055)
文摘The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kind of roller material, the high-vanadium alloy steel （HVAS）, was investigated. The results showed that the as-cast microstructures of the HVAS roller contained martensite, residual austenite, and alloy carbides. The HVAS sample quenched at 1,080 ℃ had a high hardness, and it had much higher compressive strength and abrasive wear resistance after tempering at 560 ℃ for 30 rain. The mechanical properties of the HVAS are more sufficient than the existing roller materials, which are feasible for larger machine design.
