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MATL913/MATE413 SEM report 1 Characterisation of fracture surface of plain carbon steel samples Charpy impact tested at room temperature and -80°C 1. Materials and mechanical properties Fracture...

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MATL913/MATE413 SEM report 1
Characterisation of fracture surface of plain ca
on steel samples Charpy impact tested at room
temperature and -80°C
1. Materials and mechanical properties
Fracture surfaces of two Charpy impact tested plain ca
on steel samples, at room temperature and
-80°C. The steel sample tested at RT show 11J fracture energy and the sample tested at -80°C show 1.2J
fracture energy.
2. SEM sample preparations
The fracture surfaces of the two steel samples were coated with Au before being inserted into a
SEM for observation. One optical sample was also cut from one of the Charpy samples and then
polished with 1µm diamond and followed by etching with 2% Nital to reveal the microstructure
3. SEM operation conditions
a. Instrument: JCM-6000
. Operations: A working distance of 35 mm and secondary electron imaging mode at 15
kV were chosen for the fracture surface observation. For the microstructure and EDS a
working distance of 15 mm and secondary imaging mode at 15 kV were chosen.
4. Results:
a. Fracture surfaces of the Charpy tested samples at room temperature and -80°C (see
appendix A)
. Microstructure and EDS of the steel (see appendix B)
c. Please note that you are required not only present the results but also to describe these
esults in details in order to lay a ground for your later discussions about your results.
(30 marks)

5. Discussions
The following questions should be addressed in the report:
a. Why the fracture surfaces are coated with Au? You need to discuss SEM sample
preparations in general as well. (10 marks)
. Why the working distance of 35 mm and secondary electrons were used for the fracture
surface observations? Discuss the effect of working on image quality, the image contrast
mechanisms in secondary electron images and in backscattered electron images.
(10marks)
c. Describe the characteristics of the ductile and
ittle fracture surface and explain how
the energy of the hammer of the Charpy tester was abso
ed by fracturing. (10 marks)
d. The composition of the steel was analysed with EDS. Is the ca
on content of the steel
determined by the EDS co
ect and why? (10 marks)
e. Comments on the general suitability and e
ors of EDS for determining light elements in
an alloy. (10 marks)
f. Determine the ca
on content using Fe-Fe3C phase diagram and lever rule combined
with the microstructure of the Charpy tested sample and from this result you should be
able to identify the type of ca
on steel used in the Charpy tests. (10marks)
g. At least 6 references are required in this report and they must be refe
ed in one of the
standards. (10 marks)
Appendix A: Fracture surface of Charpy tested samples
Fracture surface of Charpy sample tested at room temperature (RT)
Fracture surface of Charpy sample tested at room temperature (RT)
Fracture surface of Charpy sample tested at -80°C
Fracture surface of Charpy sample tested at -80°C
Appendix B: Microstructure and composition of the Charpy tested steel
51% pearlite and 49% Fe
ite are determined using the software called image J
(Image J software can be download free from https:
imagej.nih.gov/ij/ . User guide is available at
https:
imagej.nih.gov/ij/docs/index.html)
20 µm
Secondary electron image and area EDS microanalysis of the Charpy sample which is
polished with diamond and etched with 2% nital
JED-2300 AnalysisStation
50 µm50 µm50 µm50 µm50 µm
Title: SEM image and EDS
-------------------------
--
Instrument : JCM-6000
Volt : 15.00 kV
Mag. : x 750
Date : 2020/03/27
Pixel : 1024 x 768
XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX
keV
0
800
1600
2400
3200
4000
4800
5600
6400
7200
8000
8800
9600
Co
un
ts
C
CKsum
Mg Si SiKsum
Mn
Mn
MnKesc
Mn
Mn
Fe
Fe
Fe
Acquisition Parameter
Instrument : JCM-6000
Acc. Voltage : 15.0 kV
Probe Cu
ent: XXXXXXXXXXnA
PHA mode : T2
Real Time : 52.15 sec
Live Time : 50.00 sec
Dead Time : 4 %
Counting Rate: 7077 cps
Energy Range : XXXXXXXXXXkeV
ZAF Method Standardless Quantitative Analysis
Fitting Coefficient : 0.0319
Element XXXXXXXXXXkeV) Mass% Sigma Atom% Compound Mass% Cation XXXXXXXXXXK
C K XXXXXXXXXX XXXXXXXXXX98 XXXXXXXXXX4.4740
Mg K XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX0.1709
Si K* XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX0.3377
Mn K* XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX0.8223
Fe K XXXXXXXXXX XXXXXXXXXX64 XXXXXXXXXX94.1951
Total XXXXXXXXXX XXXXXXXXXX
Answered Same Day May 26, 2021 MATL913

Solution

Rahul answered on Jun 03 2021
143 Votes
REPORT ON X – RAY DIFFRACTION
Overview of X-Ray Diffraction
1. X-ray diffraction (XRD) mainly depends on the dual nature (particle/wave nature) of
X-rays to get idea about the structure of crystalline materials. This technique
asically used for the identification of compounds based on their diffraction pattern.
When Monochromatic incident beam interacts with target material and through the
slits it scatters of those x-rays from atoms of the target material. There are two
interference during the X-Ray diffraction which is constructive and destructive
interference. This process by crystals is defined by Bragg’s law, n(lambda) =
2dsin(theta). The direction of diffraction depends on the size and shape of the unit
cell of the material. The intensities of the waves proportional to the kind and
a
angement of atoms. Most of the materials are composed of many tiny crystallites in
all possible orientations called a polycrystalline or powder. When a polycrystalline
with randomly oriented crystallites is placed in way of X-ray beam, the beam will see
all possible interatomic planes. If the experimental angle is systematically changed
then all diffraction peaks from the powder will be detected. It has higher absorption.
There is lower amount needed during the experiment. Neighbours and isotopes
cannot be discriminated. There is hard to detect Light elements
Figure 1: X-Ray Diffraction
Application
a. It is used in sample texture evaluation, thin film analysis, investigation of
sample stress and strain monitoring of crystalline phase and structure
. It is also used in characterization of crystalline materials, determination of unit
cell dimensions, determine of modal amounts of minerals (quantitative
analysis)
c. There are also some other applications like determine crystal structures using
Rietveld refinement
Advantages
a. In this technique minimal sample preparation is required
. X-Ray based units are widely available
c. Powerful and rapid technique
d. Data interpretation is very easy
2 Synchrotron Radiation
The synchrotron radiation is an accelerator in which electron are injected and accelerated
to very high form of energy. In this generally electrons are injected at intervals of 20 ms
and accelerated at 5 GeV.
Diffraction with Monochromatic Radiation
Monochromatic radiation’s conventional source is basically long conventional practice.
A specific wavelength is selected from the radiation by using monochromator. So first of
all we fixed the wavelength and try to satisfy the
ag condition by adjusting the
orientation of the crystal.
n.lemda = 2d sin(theta)
By using synchrotron radiation double crystal a
angement is used
Advantage of Synchrotron Radiation
a It is very intense and compromises a continuous spectrum
It is polarised to higher degree and it is pulsed and modulated
c It is highly collimated
d high energy beams to penetrate deeper into matter
e Using radiation with small length helps to study the tiny feature of the target material
f The main advantage of this radiation is it can be coherent and polarised
g It can be flash at higher frequency giving the light at time structure
3 Neutron Diffraction
Neutron diffraction is a non-routine complementary technique allowing detection of light
elements, recording of higher intensity Bragg reflections at high angle, discrimination of
neighbouring elements. Neutron diffraction is new concept in the diffraction. In this
theory of scattering is worked same as x-ray diffraction. According to the wave-particle
dualism neutron are comes under the wave properties. As X-rays neutrons have a
wavelength on the order of the atomic scale (Å) and a similar interaction strength with
matter. Interference pattern generated by neutron can be use in Bragg diffraction
experiment.
There are two method from where neutron can be released from the atom. First one is
fission reactor and second one is spallation source. In fission reactor, nuclei
eaks into
lighter particle and liberate 2-3 neutron. In spallation source, proton bombardment of
lead nuclei releasing spallation neutron.
Properties of Neutron
a It has high energy for practical use
Scattering Power is independent of theta
c Mainly neutron interact with nucleus
d It has lower absorption properties
e During the experiment, large amount of sample is needed
f It is not widely available like x- ray
g Light element can be seen
h Neighbours and isotopes
Application of Neutron Diffraction
a. It is used in synthesis of catalyst
. It is used in metallurgy process
Part B
i Sample preparation is most important part to get...
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