TEM制样浅谈

A (B1 )T
Determination of orientation relationships
For a OR between matrix and precipitate phase, we can propose as follows:
Determination of orientation relationships
Contents
1 2 3 4
Preparation Operation Analysis
Summary
Contents
1 2 3 4
Preparation Operation Analysis
Summary
Preparation
Preparation of specimen
1. how to prepare? Methods, equipments, and people.
different phases
a. the determination of orientation relationships b. the atomic structure and chemical composition of interface
between
T phases
SnO2
wk.baidu.com
Grain boundary
样品基本要求： 表面“新鲜”、清洁、无氧化层 ，冲样后应去除边缘毛刺。
关键参数：
腐蚀液配方，双喷电压，温度。
合格样品： 表面非常光亮，穿孔位于样品中心，孔小而粗糙。
Preparation of TEM specimen
2. Ion polishing (离子减薄)
关键参数： 凹坑样品好坏，离子束电压、功率及入射角度。 合格样品： 表面光亮，穿孔位于样品中心，孔小而粗糙，（一旦穿孔立即停止减薄过程）。
a2 ab cos ac cos G ab cos b2 bc cos ac cos bc cos c2
Determination of orientation relationships
Determination of orientation relationships
Preparation in thoughts
1. what do you want?
2. How to get it? 3. what can we gain?
Preparation of TEM specimen

1. Chemical polishing (化学减薄/ 双喷减薄)
Mechanical polishing
Preparation in thoughts
References
Results and research methods (SAED, EDS) of others.
Prediction
The microstructures, phases, or the structure constants of
G * and I uvw can be related as: hkl
h u k G v l w
or
u h v G 1 k w l
For any crystal:
FEI TecnaiG2 20
Oxford instruments EDS detector
Contents
1 2 3 4
Preparation Operation Analysis
Summary
Operation of TEM
Method
Bright-field image: a. Microstructures or morphology analysis. b. Magnification range: 21x -700kx in TEM mode (FEI G20) c. Comparable images
Efficiency
Efficiency=Money=Time
Contents
1 2 3 4
Preparation Operation Analysis
Summary
Analysis of TEM results
The characterization of interface structure
TEM images of 2E12 alloy inT4 state
Operation of TEM
Method
Dark-field image: a. advantages: effective technique for uses involving unstained samples b. disadvantages: low light levels image. c. specimen requirement : thickness
different crystals. etc.
Device parameters
The resolution of TEM, EDS. etc.
Point resolution：0.234nm accelerating voltage ：200KV Single and double tilt specimen holders (α≤±45°β≤±40° )
Thank you for your attention!
School of Materials Science and Engineering, Central South University
Summary In a words, this is some experience I want to sharing with you-all, and I hope it would be helpful for your experiments. This is a process of learning from each other！
b) 树脂包埋：
碳膜铜网是一层方华膜+一层碳膜。 微栅是一层带微孔的方华膜+一层碳膜。 避免有机碳膜和喷碳后带来的背景干扰。 铜网一般用来看形貌像，微栅用来看 HRTEM。价格上是铜网的3倍左右。
包埋剂要求：高强度、高温稳定 性、与多种化学试剂不发生反应。 常用包埋剂：G1，G2，610等。 该种方法还可用于薄膜、涂层样品制备。
ORⅠ:
0.005 0.005 0.882 B1 0.61 0.61 0 0.887 0.887 0.01
0.005 0.005 0.882 ORⅡ: B2 0.61 0.61 0 0.887 0.887 0.01
Operation of TEM
The images of BF and DF
SAED BFI
Ag
SnO2
DFI
DFI
Operation of TEM
Method
Selected area electron diffraction (SAED)
a. the characteristics of diffraction patterns in low index directions
transformed to the corresponding parallel plane in precipitate phase by a matrix A :
u u v B v w w
h h k A k l l
For a plane (hkl), we can express in reciprocal vector:
* G* ha1 ka* la* hkl 2 3
The normal direction [uvw] can be expressed in real vector:
Iuvw ua1 va 2 wa 3
Preparation of TEM specimen

3. Replica techniques （复型技术）
Preparation of TEM specimen
3. Powders (粉末样品)
a) 直接观察：将粉末放入无水乙醇溶液中，采用超声波
震荡分散均匀后，滴在微栅上，干燥后直接进行透射 观察（适合纳米级粉末分析）。
Learning of transmission electron microscopic technology
Sharing my experience
TEM制样浅谈
School of Materials Science and Engineering, Central South University
OR I and II are the essentially same
Determination of orientation relationships
Another way to determine the ORs between matrix and precipitates is the stereographic projections method.
Ag[100]
Ag[110]
Ag[112]
Ag[111]
b. the size of constituency aperture (选区光阑)
Operation of TEM
Method
EDS: minsize of electron beam: 20nm (FEI G20) (~80nm)
a. Take notes b. Corresponding bright-field image
For the elongated octahedral shaped SnO2 precipitate,
ORⅠ:
(111 Ag //(101 SnO2 [110] / /[010] ) )
Ag
SnO2
For the plate shaped SnO2 precipitate, ORⅡ:
(111 Ag //(101 SnO2 [112]Ag / /[101]SnO2 ) )
Determination of orientation relationships
A direction in matrix phase can be transformed to the corresponding parallel
direction in precipitate phase by a matrix B, and a plane in matrix can be
Martensite in Ti alloy
Precipitates in Al alloy
Ag matrix composite
Various kinds of interface structures
Determination of orientation relationships
Determination of orientation relationships