Nanocrystalline E and η electron compounds and supersaturated solid solution of the Cu-Sn system have been prepared by mechanical alloying of elemental Cu and Sn powders. The atomie alloying and microstructure of the...Nanocrystalline E and η electron compounds and supersaturated solid solution of the Cu-Sn system have been prepared by mechanical alloying of elemental Cu and Sn powders. The atomie alloying and microstructure of the resultant alloys have been investigated by XRD, DSC and 119Sn Mossbauer spectroscopy. A little amount of SnO2 was detected by Mossbauer spectroscopy, although no trace of diffiaction peaks occurred in the XRD pattern. Thus the spectra for all the milled samples should be fitted using two quadrupole-splitting doublets: one corre sponding to SnO2, the other corresponding to the resultant alloys. The composition dependence of the hyperfine parameters has been eXtensively discussed and explained well with respect to oxidation, sudece effect resulting from grain refinement, coordination environment asymmetry and distortion caused or/and induced by mechanical alloying.展开更多
When a transformable B2 precipitate is embedded in an amorphous matrix,it is often experimentally observed that the crystalline-amorphous interface not only serves as an initiation site for the martensitic transformat...When a transformable B2 precipitate is embedded in an amorphous matrix,it is often experimentally observed that the crystalline-amorphous interface not only serves as an initiation site for the martensitic transformation due to local stress concentrations,but also as an inhibitor to stabilize the transformation,the latter being attributed to the“confinement effect”exerted by the amorphous matrix,according to the Eshelby solution.These two seemingly incongruous factors are examined in this study using molecular dynamics simulations from an atomic interaction perspective.An innate strain gradient in the vicinity of the crystalline-amorphous interface is identified.The actual interface,the compressive/dilatative transition,and the interfacial maximum strain are investigated to differentiate from the conventional“interface”located within a distance of a few nanometers.Our innate interfacial elastic strain field model is applicable for the design of materials with a higher degree of martensitic transformation and controllable stress concentration,even in cryogenic environments.展开更多
文摘Nanocrystalline E and η electron compounds and supersaturated solid solution of the Cu-Sn system have been prepared by mechanical alloying of elemental Cu and Sn powders. The atomie alloying and microstructure of the resultant alloys have been investigated by XRD, DSC and 119Sn Mossbauer spectroscopy. A little amount of SnO2 was detected by Mossbauer spectroscopy, although no trace of diffiaction peaks occurred in the XRD pattern. Thus the spectra for all the milled samples should be fitted using two quadrupole-splitting doublets: one corre sponding to SnO2, the other corresponding to the resultant alloys. The composition dependence of the hyperfine parameters has been eXtensively discussed and explained well with respect to oxidation, sudece effect resulting from grain refinement, coordination environment asymmetry and distortion caused or/and induced by mechanical alloying.
基金supported by the National Natural Science Foundation of China(No.51601019,52001184,52071089,52071217)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2019B030302010)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010233,2019A1515110472).
文摘When a transformable B2 precipitate is embedded in an amorphous matrix,it is often experimentally observed that the crystalline-amorphous interface not only serves as an initiation site for the martensitic transformation due to local stress concentrations,but also as an inhibitor to stabilize the transformation,the latter being attributed to the“confinement effect”exerted by the amorphous matrix,according to the Eshelby solution.These two seemingly incongruous factors are examined in this study using molecular dynamics simulations from an atomic interaction perspective.An innate strain gradient in the vicinity of the crystalline-amorphous interface is identified.The actual interface,the compressive/dilatative transition,and the interfacial maximum strain are investigated to differentiate from the conventional“interface”located within a distance of a few nanometers.Our innate interfacial elastic strain field model is applicable for the design of materials with a higher degree of martensitic transformation and controllable stress concentration,even in cryogenic environments.
