Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a ...Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a thickness of 15 mm. For different process parameters, the optimum FSW conditions of ECAPed AZ31 magnesium alloys were examined. The basic characterization of weld formation and the mechanical properties of the joints were discussed. The results show that the effect of welding parameters on welding quality was evident and welding quality was sensitive to welding speed. Sound joints could be obtained when the welding speed was 37.5 mm/min and the rotation speed of the stir tool was 750 r/min. The maximum tensile strength （270 MPa） of FSW was 91% that of the base materials. The value of microhardness varied between advancing side and retreating side because of the speed field near the pin of the stir tool, which weakened the deformed stress field. The value of microhardness of the welding zone was lower than that of the base materials. The maximum value was located near the heat-affected zone （HAZ）. Remarkable ductile character was observed from the fracture morphologies of welded joints.展开更多
Persistent gastritis induced by Helicobacter pylori(H.pylori)is the strongest known risk factor for gastric cancer(GC).H.pylori is prevalent in about 50%world's population,while it causes cancer in less than 2%of ...Persistent gastritis induced by Helicobacter pylori(H.pylori)is the strongest known risk factor for gastric cancer(GC).H.pylori is prevalent in about 50%world's population,while it causes cancer in less than 2%of exposed individuals.1 Our studies found that H.pylori infection can induce oncogenic properties in AGS cells by deregulating multiple factors associated with the cell cycle,apoptosis,and other important events associated with cancer progression.展开更多
To improve the efficiency of iron recovery from steel slag and reduce the wear-and-tear on facilities, a new method was proposed by adding a secondary screen sizer to the magnetic separation process according to grain...To improve the efficiency of iron recovery from steel slag and reduce the wear-and-tear on facilities, a new method was proposed by adding a secondary screen sizer to the magnetic separation process according to grain size distribution of magnetic iron （M-Fe） in the slag. The final recycling efficiency was evaluated by calculating the percentage of recycled M-Fe to the maximum amount of M-Fe that could be recovered. Three types of slags, namely basic oxygen furnace slag, desul- furization slag, and iron ladle slag, were studied, and the results showed that the optimized re- covery efficieneies were 93.20%, 92. 48%, and 85.82% respectively, and the recycling efficien eies were improved by 9.58%, 7.11%, and 6.24% respectively. Furthermore, the abrasion between the mill equipment and the remaining slags was significantly reduced owing to the efficient recovery of larger M-Fe particles. In addition, the using amount of grinding balls was reduced by 0. 46 kg when every 1 t steel slag was processed.展开更多
In the present study,Al_(86)Ni_(8)Y_(6) and Al_(86)Ni_(6)Y_(4.5)Co_(2)La_(1.5) bulk amorphous nanocomposites were synthesized by spark plasma sintering of milled melt spun ribbon particles.The as-cast ribbons were of ...In the present study,Al_(86)Ni_(8)Y_(6) and Al_(86)Ni_(6)Y_(4.5)Co_(2)La_(1.5) bulk amorphous nanocomposites were synthesized by spark plasma sintering of milled melt spun ribbon particles.The as-cast ribbons were of near amorphous nature with minute amount of FCC Al embedded in the amorphous matrix.Milling of the ribbons resulted in partial devitrifi cation due to mechanical crystallization.The milled ribbon particles were sintered in the temperature and pressure range of 300-500℃ and 500-700 MPa,respectively.It was observed that nominal amount of amorphous phase was retained at 500℃ and 500 MPa.With increase in sintering pressure and decrease in sintering temperature,the amount of crystalline phase evolution decreased,and maximum amount of amorphous phase was retained at 300℃ and 700 MPa.The microstructure consisting of amorphous phase embedded with hard intermetallic phases led to increase in the nanohardness of Al_(86)Ni_(8)Y_(6) and Al_(86)Ni_(6)Y_(4.5)Co_(2)La_(1.5) as-cast ribbons from 3.26±0.59 GPa and 3.81±0.58 GPa to 6.06±0.70 GPa and 6.14±0.82 GPa,respectively,for the corresponding consolidated amorphous nanocomposite.Microhardness of the three and five component system bulk samples was 4.19±0.13GPa and 3.6±0.13 GPa,respectively.展开更多
Multi-phase microstructures having good ductility may replace the conventional microstructures in different technological applications such as pressure vessels.Mechanical properties including the fracture behavior and...Multi-phase microstructures having good ductility may replace the conventional microstructures in different technological applications such as pressure vessels.Mechanical properties including the fracture behavior and the service life of pressure vessels are strongly affected by the microstructure.The objective of this study was to investigate the correlation between different dual-phase microstructures and mechanical properties of 42CrMo4 (AISI 4140) steel.To produce the martensite-bainite (M-B),the martensite-ferrite (M-F),and the ferrite-bainite (F-B) microstructures,the step quenching heat treatment was used.Mechanical properties of heat treated samples including the strength,ductility,and impact energy were measured.Tensile experiments revealed a discontinuous yielding in the F-B specimen with ferritic matrix.Fracto\graphic results showed high concentration bright facets (BFs) on broken specimen surfaces indicating the brittle cleavage fracture was the predominant mechanism in the dual-phase microstructures.展开更多
The ever-increasing number of materials science articles makes it hard to infer chemistry-structure-property relations from literature.We used natural language processing methods to automatically extract material prop...The ever-increasing number of materials science articles makes it hard to infer chemistry-structure-property relations from literature.We used natural language processing methods to automatically extract material property data from the abstracts of polymer literature.As a component of our pipeline,we trained MaterialsBERT,a language model,using 2.4 million materials science abstracts,which outperforms other baseline models in three out of five named entity recognition datasets.Using this pipeline,we obtained~300,000 material property records from~130,000 abstracts in 60 hours.The extracted data was analyzed for a diverse range of applications such as fuel cells,supercapacitors,and polymer solar cells to recover non-trivial insights.The data extracted through our pipeline is made available at polymerscholar.org which can be used to locate material property data recorded in abstracts.This work demonstrates the feasibility of an automatic pipeline that starts from published literature and ends with extracted material property information.展开更多
文摘Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a thickness of 15 mm. For different process parameters, the optimum FSW conditions of ECAPed AZ31 magnesium alloys were examined. The basic characterization of weld formation and the mechanical properties of the joints were discussed. The results show that the effect of welding parameters on welding quality was evident and welding quality was sensitive to welding speed. Sound joints could be obtained when the welding speed was 37.5 mm/min and the rotation speed of the stir tool was 750 r/min. The maximum tensile strength （270 MPa） of FSW was 91% that of the base materials. The value of microhardness varied between advancing side and retreating side because of the speed field near the pin of the stir tool, which weakened the deformed stress field. The value of microhardness of the welding zone was lower than that of the base materials. The maximum value was located near the heat-affected zone （HAZ）. Remarkable ductile character was observed from the fracture morphologies of welded joints.
文摘Persistent gastritis induced by Helicobacter pylori(H.pylori)is the strongest known risk factor for gastric cancer(GC).H.pylori is prevalent in about 50%world's population,while it causes cancer in less than 2%of exposed individuals.1 Our studies found that H.pylori infection can induce oncogenic properties in AGS cells by deregulating multiple factors associated with the cell cycle,apoptosis,and other important events associated with cancer progression.
基金the funding of Chongqing Application and Development Project of China(cstc2014yykfB100007)
文摘To improve the efficiency of iron recovery from steel slag and reduce the wear-and-tear on facilities, a new method was proposed by adding a secondary screen sizer to the magnetic separation process according to grain size distribution of magnetic iron （M-Fe） in the slag. The final recycling efficiency was evaluated by calculating the percentage of recycled M-Fe to the maximum amount of M-Fe that could be recovered. Three types of slags, namely basic oxygen furnace slag, desul- furization slag, and iron ladle slag, were studied, and the results showed that the optimized re- covery efficieneies were 93.20%, 92. 48%, and 85.82% respectively, and the recycling efficien eies were improved by 9.58%, 7.11%, and 6.24% respectively. Furthermore, the abrasion between the mill equipment and the remaining slags was significantly reduced owing to the efficient recovery of larger M-Fe particles. In addition, the using amount of grinding balls was reduced by 0. 46 kg when every 1 t steel slag was processed.
基金was fi nancially supported by the Science and Engineering Research Board,Department of Science&Technology,Government of India(Grant No.SB/S3/ME/0044/2013)。
文摘In the present study,Al_(86)Ni_(8)Y_(6) and Al_(86)Ni_(6)Y_(4.5)Co_(2)La_(1.5) bulk amorphous nanocomposites were synthesized by spark plasma sintering of milled melt spun ribbon particles.The as-cast ribbons were of near amorphous nature with minute amount of FCC Al embedded in the amorphous matrix.Milling of the ribbons resulted in partial devitrifi cation due to mechanical crystallization.The milled ribbon particles were sintered in the temperature and pressure range of 300-500℃ and 500-700 MPa,respectively.It was observed that nominal amount of amorphous phase was retained at 500℃ and 500 MPa.With increase in sintering pressure and decrease in sintering temperature,the amount of crystalline phase evolution decreased,and maximum amount of amorphous phase was retained at 300℃ and 700 MPa.The microstructure consisting of amorphous phase embedded with hard intermetallic phases led to increase in the nanohardness of Al_(86)Ni_(8)Y_(6) and Al_(86)Ni_(6)Y_(4.5)Co_(2)La_(1.5) as-cast ribbons from 3.26±0.59 GPa and 3.81±0.58 GPa to 6.06±0.70 GPa and 6.14±0.82 GPa,respectively,for the corresponding consolidated amorphous nanocomposite.Microhardness of the three and five component system bulk samples was 4.19±0.13GPa and 3.6±0.13 GPa,respectively.
文摘Multi-phase microstructures having good ductility may replace the conventional microstructures in different technological applications such as pressure vessels.Mechanical properties including the fracture behavior and the service life of pressure vessels are strongly affected by the microstructure.The objective of this study was to investigate the correlation between different dual-phase microstructures and mechanical properties of 42CrMo4 (AISI 4140) steel.To produce the martensite-bainite (M-B),the martensite-ferrite (M-F),and the ferrite-bainite (F-B) microstructures,the step quenching heat treatment was used.Mechanical properties of heat treated samples including the strength,ductility,and impact energy were measured.Tensile experiments revealed a discontinuous yielding in the F-B specimen with ferritic matrix.Fracto\graphic results showed high concentration bright facets (BFs) on broken specimen surfaces indicating the brittle cleavage fracture was the predominant mechanism in the dual-phase microstructures.
基金This work was supported by the Office of Naval Research through grants N00014-19-1-2103 and N00014-20-1-2175.Helpful discussions and feedback from Dr.Lihua Chen are acknowledged.Pranav Shetty was partially funded by a fellowship by JPMorgan Chase&Co.that helped to support this research.Any views or opinions expressed herein are solely those of the authors listed,and may differ from the views and opinions expressed by JPMorgan Chase&Co.or its affiliates.
文摘The ever-increasing number of materials science articles makes it hard to infer chemistry-structure-property relations from literature.We used natural language processing methods to automatically extract material property data from the abstracts of polymer literature.As a component of our pipeline,we trained MaterialsBERT,a language model,using 2.4 million materials science abstracts,which outperforms other baseline models in three out of five named entity recognition datasets.Using this pipeline,we obtained~300,000 material property records from~130,000 abstracts in 60 hours.The extracted data was analyzed for a diverse range of applications such as fuel cells,supercapacitors,and polymer solar cells to recover non-trivial insights.The data extracted through our pipeline is made available at polymerscholar.org which can be used to locate material property data recorded in abstracts.This work demonstrates the feasibility of an automatic pipeline that starts from published literature and ends with extracted material property information.
