The State University of New York at Albany ion scanning microprobe has been used for materials characterization. Focused proton and helium ion beams have been used. Rutherford backscattering spectroscopy (RBS) and par...The State University of New York at Albany ion scanning microprobe has been used for materials characterization. Focused proton and helium ion beams have been used. Rutherford backscattering spectroscopy (RBS) and particle - induced X - ray emission (PIXE) analysis have been performed on microelectronic circuits with a spatial resolution of approximately 2 μm. Studies on thin films of superconductors will be presented. Several examples of chemical and microstructural analysis will be given.展开更多
Behaviors of displacive phase-transforming materials above the temperature of transformation,where abnormal thermal,elastic,magnetic properties are often observed,are mostly explained by intrinsic peculiarities in ele...Behaviors of displacive phase-transforming materials above the temperature of transformation,where abnormal thermal,elastic,magnetic properties are often observed,are mostly explained by intrinsic peculiarities in electronic/atomic structure.Here,we show these properties may also be attributed to extrinsic effects caused by a thermoelastic equilibrium in highly defected pretransitional materials.We demonstrate that the stress concentration near stress-generating defects such as dislocations and coherent precipitates could result in the stress-induced transformation within nanoscale regions,producing equilibrium embryos of the product phase.These nanoembryos in thermoelastic equilibrium could anhysteretically change their equilibrium size in response to changes in applied stress or magnetic fields leading to superelasticity or supermagnetostriction.Similar response to cooling may explain the observed diffuse phase transformation,changes in the coefficient of thermal expansion and effective elastic modulus,which,in turn,may explain the invar and elinvar behaviors.展开更多
文摘The State University of New York at Albany ion scanning microprobe has been used for materials characterization. Focused proton and helium ion beams have been used. Rutherford backscattering spectroscopy (RBS) and particle - induced X - ray emission (PIXE) analysis have been performed on microelectronic circuits with a spatial resolution of approximately 2 μm. Studies on thin films of superconductors will be presented. Several examples of chemical and microstructural analysis will be given.
基金This work was partially supported by the National Natural Science Foundation of China(No.11474167).
文摘Behaviors of displacive phase-transforming materials above the temperature of transformation,where abnormal thermal,elastic,magnetic properties are often observed,are mostly explained by intrinsic peculiarities in electronic/atomic structure.Here,we show these properties may also be attributed to extrinsic effects caused by a thermoelastic equilibrium in highly defected pretransitional materials.We demonstrate that the stress concentration near stress-generating defects such as dislocations and coherent precipitates could result in the stress-induced transformation within nanoscale regions,producing equilibrium embryos of the product phase.These nanoembryos in thermoelastic equilibrium could anhysteretically change their equilibrium size in response to changes in applied stress or magnetic fields leading to superelasticity or supermagnetostriction.Similar response to cooling may explain the observed diffuse phase transformation,changes in the coefficient of thermal expansion and effective elastic modulus,which,in turn,may explain the invar and elinvar behaviors.
