The influence of high pressure and manganese addition on Fe-rich phases(FRPs)and mechanical properties of Al-14Si-2Fe alloy with rheo-squeeze casting(RSC)was investigated.The semi-solid alloy melt was treated by ultra...The influence of high pressure and manganese addition on Fe-rich phases(FRPs)and mechanical properties of Al-14Si-2Fe alloy with rheo-squeeze casting(RSC)was investigated.The semi-solid alloy melt was treated by ultrasonic vibration(UV)firstly,and then formed by squeeze casting(SC).Results show that the FRPs in as-cast SC alloys are composed of coarseβ-Al5(Fe,Mn)Si,δ-Al4(Fe,Mn)Si2 and bone-shapedα-Al15(Fe,Mn)3Si2 phases when the pressure is 0 MPa.With RSC process,the FRPs are first refined by UV,and then the solidification under pressure further causes the grains to become smaller.The peritectic transformation occurs during the formation ofαphase.For the alloy with the same composition,the ultimate tensile strength(UTS)of RSC sample is higher than that of the SC sample.With the same forming process,the UTS of Al-14Si-2Fe-0.8Mn alloy is higher than that of Al-14Si-2Fe-0.4Mn alloy.展开更多
The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated. A combination of the swirl enthalpy equilibration device （SEED） process, isothermal holding u...The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated. A combination of the swirl enthalpy equilibration device （SEED） process, isothermal holding using insulation and addition of solid alloy during swirling was introduced as a novel method to improve the processability of semi solid slurry. The effects of isothermal holding and the addition of solid alloy on the temperature gradient between the centre and the wall and on the formation of a（Al） particles were examined. In additional tests, phosphorus and strontium were added to the molten metal to refine the primary and eutectic silicon structure to facilitate semi solid processing. The results show that the combination of the SEED process with two additional processing steps can produce semi-solid A390 alloys that can be rheoprocessed. The microstructure reveals an adequate amount of non-dendritic a（Al） globules surrounded by liquid, which greatly improves the processability of semi-solid slurry.展开更多
Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier...Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.展开更多
基金Project(51605342) supported by the National Natural Science Foundation of ChinaProject(2015CFB431) supported by the Natural Science Foundation of Hubei Province,China+1 种基金Project(K201520) supported by the Science Research Foundation of Wuhan Institute of Technology,ChinaProject(2016KA01) supported by the Open Research Fund Program of Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety,China
文摘The influence of high pressure and manganese addition on Fe-rich phases(FRPs)and mechanical properties of Al-14Si-2Fe alloy with rheo-squeeze casting(RSC)was investigated.The semi-solid alloy melt was treated by ultrasonic vibration(UV)firstly,and then formed by squeeze casting(SC).Results show that the FRPs in as-cast SC alloys are composed of coarseβ-Al5(Fe,Mn)Si,δ-Al4(Fe,Mn)Si2 and bone-shapedα-Al15(Fe,Mn)3Si2 phases when the pressure is 0 MPa.With RSC process,the FRPs are first refined by UV,and then the solidification under pressure further causes the grains to become smaller.The peritectic transformation occurs during the formation ofαphase.For the alloy with the same composition,the ultimate tensile strength(UTS)of RSC sample is higher than that of the SC sample.With the same forming process,the UTS of Al-14Si-2Fe-0.8Mn alloy is higher than that of Al-14Si-2Fe-0.4Mn alloy.
基金the financial support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Rio Tinto Alcan through the NSERC Industrial Research Chair in Metallurgy of Aluminum Transformation at Université du Québec à Chicoutimi
文摘The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated. A combination of the swirl enthalpy equilibration device （SEED） process, isothermal holding using insulation and addition of solid alloy during swirling was introduced as a novel method to improve the processability of semi solid slurry. The effects of isothermal holding and the addition of solid alloy on the temperature gradient between the centre and the wall and on the formation of a（Al） particles were examined. In additional tests, phosphorus and strontium were added to the molten metal to refine the primary and eutectic silicon structure to facilitate semi solid processing. The results show that the combination of the SEED process with two additional processing steps can produce semi-solid A390 alloys that can be rheoprocessed. The microstructure reveals an adequate amount of non-dendritic a（Al） globules surrounded by liquid, which greatly improves the processability of semi-solid slurry.
基金the financial support by the Fundamental Research Funds for the Central Universities (No.2010QNA14)
文摘Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.
