Wen DENG Liangyue XIONG Chiwei LUNG International Centre for Materials Physics
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
ChinaShuhe WANG Jianting GUO Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni and Al atoms and make the electronic structure in those locations similar to that in bulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in the crystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in the increase of the density of valent electrons,thus increased the bonding cohesion in bulk.The im- provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda- ry effect”and“bulk effect”of B,which correlated with their electronic structure.
关键词:
electronic structure
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null
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null
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null
Douxing LI and Hengqiang YE (Laboratory of Atomic imaging of Solids
,
Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
110015
,
China)
材料科学技术（英文）
The present paper summarizes the current status of high resolution electron microscopy (HREM)and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction,subnanometer level analysis, image simulation and image processing.
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