上海交通大学：《材料组织结构表征》课程教学资源（课件讲义）高分辨透射电子显微术

High Resolution Electron Microscopy 高分辨电子显微本

High Resolution Electron Microscopy 高分辨电子显微术

What are we looking at in HREM? How can we look? Why are contrast generated? Unit Amorphous Sheet Top Side 1 mm The dark spots are Si-O-Si columns that correspond with the top and side views

• What are we looking at in HREM? • How can we look? • Why are contrast generated? 2 The dark spots are Si-O-Si columns that correspond with the top and side views

L12-Ni3Al viewing along [001] B//110] 3 nm 3

L12 -Ni3Al 3

Ni-Al-Re 2nm Y 4 X.X.Yu et al.Journal of Alloys and Compounds 582 (2014)299-304

4 X.X. Yu et al. / Journal of Alloys and Compounds 582 (2014) 299–304

● 晶界 单

• 晶界

孪晶 02645A Twin SE 5um

• 孪晶 ·

·纳米金颗粒 40nm 纳米管

• 纳米金颗粒 纳米管

Imaging atom columns/lattice planes Go to a zone axis orientation Low index zone axis is preferred ·eg.[110],[001]or[111]for fcc It is because of the resolution limit of the EMs. 8

Imaging atom columns/lattice planes • Go to a zone axis orientation • Low index zone axis is preferred • eg. [110], [001] or [111] for fcc • It is because of the resolution limit of the EMs. 8

Imaging using more than one beam ●透射波 ·衍射波 (a) (b) (c) Bright field Dark field HREM Amplitude contrast 9

Imaging using more than one beam 9 Bright field Dark field HREM Amplitude contrast

衍射衬度和相位衬度 试样 28 20 物镜 物镜光阑 后焦平面 像平面 (a)散射吸收衬度 (b)相位衬度 (振幅衬度)

衍射衬度和相位衬度 • Yi