This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experi...This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.展开更多
Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological ...Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability （GFA） and supercooled liquid region （ATx）. The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ATX. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.展开更多
Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to descr...Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to describe the detailed local structure of this alloy. It was revealed Co7TalB2, Co6TalB2 and CosTa2B4 among the dominant （0 3 6 0）, （0 4 4 0）, （0 1 10 2） and （0 3 6 4） polyhedra were the basic local structure units in CossTal0B3s amorphous alloy. Furthermore, most of the dominant poly- hedra tended to have Ta atoms involved and these polyhedra may have a critical role during glass formation.展开更多
文摘This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.
基金supported by the National Basic Research Program of China (Grant No. 2007CB613900)the National Natural Science Foundation of China (Grant No. 51071008)the Fundamental Research Funds for the Central Universities
文摘Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability （GFA） and supercooled liquid region （ATx）. The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ATX. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.
基金supported by the National Natural Science Foundation of China (Grant No. 51101004)the Fundamental Research Funds for the Central Universities
文摘Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to describe the detailed local structure of this alloy. It was revealed Co7TalB2, Co6TalB2 and CosTa2B4 among the dominant （0 3 6 0）, （0 4 4 0）, （0 1 10 2） and （0 3 6 4） polyhedra were the basic local structure units in CossTal0B3s amorphous alloy. Furthermore, most of the dominant poly- hedra tended to have Ta atoms involved and these polyhedra may have a critical role during glass formation.
