An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstru...An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstruc- rural investigations, hierarchical nanotwinned lamellar AISc bundles with embedded micron-/submicron-sized AI2Sc and AISc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of -1.85 GPa to- gether with pronounced work hardening and a large plasticity of -14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AISc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of mierocracks formed by local stress transition.展开更多
Rice with polyembryony characterized bytwin seedlings is a good genetic tool for apomixisresearch.A study on the effect of five plantgrowth regulators(IAA,KT,GA,2,4-D and6-BAP)on rate of twin seedlings in 3 rice varie...Rice with polyembryony characterized bytwin seedlings is a good genetic tool for apomixisresearch.A study on the effect of five plantgrowth regulators(IAA,KT,GA,2,4-D and6-BAP)on rate of twin seedlings in 3 rice varie.ties with polyembryony(Shuang 3,Shuang 13and Lu 52)was conducted.The results showed展开更多
The aim of this study was to examine and quantify the growth of extension twins and the associated texture change in an extruded AM30 magnesium alloy during compression along the extrusion direction. Three stages of t...The aim of this study was to examine and quantify the growth of extension twins and the associated texture change in an extruded AM30 magnesium alloy during compression along the extrusion direction. Three stages of twin growth with increasing strain were observed due to twin-dislocation interactions, together with increasing texture volume fraction of {1210}〈0001〉 and {01- 10}〈0001〉 components. Stage I was characterized by a relatively slow and gradually accelerating growth. A steady-state twin growth was reached in stage II, where the twin width increased linearly with increasing strain. Stage III twin growth became decelerated, exhibiting a plateau-like character.展开更多
Nickel coatings with different microstructures were synthesized by pulse jet electrodeposition technique.Their morphology and microstructure were investigated by scanning electron microscopy（SEM）and transmission ele...Nickel coatings with different microstructures were synthesized by pulse jet electrodeposition technique.Their morphology and microstructure were investigated by scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The corrosion property of the coatings was studied by using polarization,electrochemical impedance spectroscopy（EIS）,potential of zero free charge（PZFC） measurements and Mott-Schottky（M-S） relationship.The results showed that the coating with grain size of 50 nm possessed higher corrosion resistance than that with grain size of 10 nm.This abnormal behavior may be related to the existence of nanoscale twins in the coatings and the lower concentration of acceptor in the passive films.展开更多
基金Supported by the Scientific Research Foundation of Xi’an University of Technology under Grant No 101-451115007the National Basic Research Program of China under Grant No 2007CB613900+1 种基金the National Natural Science Foundation of China under Grant No 51174161the Pivot Innovation Team of Shaanxi Electric Materials and Infiltration Technique under Grant No 2012KCT-25
文摘An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstruc- rural investigations, hierarchical nanotwinned lamellar AISc bundles with embedded micron-/submicron-sized AI2Sc and AISc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of -1.85 GPa to- gether with pronounced work hardening and a large plasticity of -14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AISc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of mierocracks formed by local stress transition.
文摘Rice with polyembryony characterized bytwin seedlings is a good genetic tool for apomixisresearch.A study on the effect of five plantgrowth regulators(IAA,KT,GA,2,4-D and6-BAP)on rate of twin seedlings in 3 rice varie.ties with polyembryony(Shuang 3,Shuang 13and Lu 52)was conducted.The results showed
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)AUTO21 Networks of Centres of Excellence of Canada for providing financial support
文摘The aim of this study was to examine and quantify the growth of extension twins and the associated texture change in an extruded AM30 magnesium alloy during compression along the extrusion direction. Three stages of twin growth with increasing strain were observed due to twin-dislocation interactions, together with increasing texture volume fraction of {1210}〈0001〉 and {01- 10}〈0001〉 components. Stage I was characterized by a relatively slow and gradually accelerating growth. A steady-state twin growth was reached in stage II, where the twin width increased linearly with increasing strain. Stage III twin growth became decelerated, exhibiting a plateau-like character.
基金financial support from the National Basic Research Program of China (No.2014CB643301)the National Natural Science Foundation of China (Nos.50971050 and 51001036)+3 种基金the Program for New Century Excellent Talents in University (No.NCET-11-0575)the Ministry of Science and Technology of the People’s Republic of China (No.2012FY113000the Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University)Ministry of Education (HEUCF20151011)
文摘Nickel coatings with different microstructures were synthesized by pulse jet electrodeposition technique.Their morphology and microstructure were investigated by scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The corrosion property of the coatings was studied by using polarization,electrochemical impedance spectroscopy（EIS）,potential of zero free charge（PZFC） measurements and Mott-Schottky（M-S） relationship.The results showed that the coating with grain size of 50 nm possessed higher corrosion resistance than that with grain size of 10 nm.This abnormal behavior may be related to the existence of nanoscale twins in the coatings and the lower concentration of acceptor in the passive films.
