Aluminium matrix composite reinforced by Al2O3 particles was produced by adding NH4AlO（OH）HCO3 into molten aluminum.The mechanical properties and wear behavior of the as-fabricated composites were studied.The result...Aluminium matrix composite reinforced by Al2O3 particles was produced by adding NH4AlO（OH）HCO3 into molten aluminum.The mechanical properties and wear behavior of the as-fabricated composites were studied.The results show that during stirring γ-Al2O3 particles were formed via decomposition reaction of NH4AlO（OH）HCO3,and the distribution of Al2O3 particles is more uniform in the matrix aluminum than directly added Al2O3 into molten aluminum.The density and the hardness values of the as-fabricated composites increase with increasing the particle volume fraction,while the tensile strength of the composites decreases with increasing the volume fraction of the Al2O3 particles.The wear rate of the composites decreases with increasing the volume fraction of the particle and loading.The in situ formed Al2O3/Al composite by adding NH4AlO（OH）HCO3 shows more superior mechanical and wear behaviors than that prepared by directly adding Al2O3 particles.展开更多
This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their appl...This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.展开更多
This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used f...This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used for joining of acrylonitrile butadiene styrene(ABS)composites.The dissimilar thermoplastics were processed for maintaining a useful range of melt flow properties followed by preparation of feed stock filament for fused deposition modeling(FDM)process through screw extrusion.Finally,3D printed PA6 based consumable rapid tool(RT)was prepared for MFSW.The joints prepared were subjected to flexural,hardness,morphological and thermal testing.The study has suggested the that maximum mechanical strength was obtained for sample welded at 1400 r/min,50 mm/min transverse speed and 3 mm plunge depth,whereas the minimum mechanical strength was obtained for sample welded at 1000 r/min,30 mm/min transverse speed and 2 mm plunge depth.The results are also supported with thermal analysis and photomicrographs.展开更多
基金Project(2009BAE80B01)supported by the Ministry of Science and Technology,China
文摘Aluminium matrix composite reinforced by Al2O3 particles was produced by adding NH4AlO（OH）HCO3 into molten aluminum.The mechanical properties and wear behavior of the as-fabricated composites were studied.The results show that during stirring γ-Al2O3 particles were formed via decomposition reaction of NH4AlO（OH）HCO3,and the distribution of Al2O3 particles is more uniform in the matrix aluminum than directly added Al2O3 into molten aluminum.The density and the hardness values of the as-fabricated composites increase with increasing the particle volume fraction,while the tensile strength of the composites decreases with increasing the volume fraction of the Al2O3 particles.The wear rate of the composites decreases with increasing the volume fraction of the particle and loading.The in situ formed Al2O3/Al composite by adding NH4AlO（OH）HCO3 shows more superior mechanical and wear behaviors than that prepared by directly adding Al2O3 particles.
基金Projects(51775365,51405329) supported by the National Natural Science Foundation of ChinaProject(2015M570239) supported by the China Postdoctoral Science Foundation
文摘This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.
文摘This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used for joining of acrylonitrile butadiene styrene(ABS)composites.The dissimilar thermoplastics were processed for maintaining a useful range of melt flow properties followed by preparation of feed stock filament for fused deposition modeling(FDM)process through screw extrusion.Finally,3D printed PA6 based consumable rapid tool(RT)was prepared for MFSW.The joints prepared were subjected to flexural,hardness,morphological and thermal testing.The study has suggested the that maximum mechanical strength was obtained for sample welded at 1400 r/min,50 mm/min transverse speed and 3 mm plunge depth,whereas the minimum mechanical strength was obtained for sample welded at 1000 r/min,30 mm/min transverse speed and 2 mm plunge depth.The results are also supported with thermal analysis and photomicrographs.
