Question is in the file.MATL913/MATE413 SEM report 1 Characterisation of fracture surface of plain...

Question

Question is in the file.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 surfaces of two Charpy impact tested plain carbon 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   b. 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)  b. 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  results 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)  b. 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 brittle fracture surface and explain how  the energy of the hammer of the Charpy tester was absorbed by fracturing. (10 marks)  d. The composition of the steel was analysed with EDS. Is the carbon content of the steel  determined by the EDS correct and why? (10 marks)  e. Comments on the general suitability and errors of EDS for determining light elements in  an alloy. (10 marks)  f. Determine the carbon 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 carbon steel used in the Charpy tests. (10marks)  g. At least 6 references are required in this report and they must be referred 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% Ferrite 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  0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 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 Current: 1.00000 nA  PHA mode     : T2  Real Time    : 52.15 sec  Live Time    : 50.00 sec  Dead Time    : 4 %  Counting Rate: 7077 cps  Energy Range :  0 - 20 keV ZAF Method Standardless Quantitative Analysis  Fitting Coefficient : 0.0319  Element        (keV)   Mass%   Sigma   Atom%  Compound   Mass%  Cation         K   C K           0.277   29.80    0.05   65.98                              4.4740  Mg K           1.253    0.54    0.04    0.59                              0.1709  Si K*          1.739    0.52    0.02    0.49                              0.3377  Mn K*          5.894    0.61    0.03    0.30                              0.8223  Fe K           6.398   68.53    0.11   32.64                             94.1951  Total                 100.00          100.00

Rahul · Accepted Answer

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 
basically 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 
arrangement 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 
b. 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 
b. 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 brag condition by adjusting the 
orientation of the crystal.   
n.lemda = 2d sin(theta) 
By using synchrotron radiation double crystal arrangement is used 
Advantage of Synchrotron Radiation 
a It is very intense and compromises a continuous spectrum  
b 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 breaks 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 
b 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  
b.

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...

Answer To: MATL913/MATE413 SEM report 1 Characterisation of fracture surface of plain carbon steel samples...

Answer To This Question Is Available To Download

Related Questions & Answers

Submit New Assignment