it's cute ( 可爱 )……… but does it do anything??. this image, taken under a microscope,...
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It's cute (可爱 )………It's cute (可爱 )………
But does it DO anything??
But does it DO anything??
This image, taken under a microscope, shows that a 'duplex stainless steel' has two phases - austenite (AUS) & ferrite (FE)
This image, taken under a microscope, shows that a 'duplex stainless steel' has two phases - austenite (AUS) & ferrite (FE)
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
Every material has a unique x-ray powder pattern
Every PHASE has a unique powder pattern
Every material has a unique x-ray powder pattern
Every PHASE has a unique powder pattern
AUS
FE
This is the X-ray diffraction patternThis is the X-ray diffraction pattern
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
AUS
FE
The X-ray diffraction pattern tells us this
The X-ray diffraction pattern tells us this
How?How?
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
We use the Powder Diffraction File database (the PDF) and a search system
We use the Powder Diffraction File database (the PDF) and a search system
History
1938 Hanawalt paper on first database and search method
1941 ASTM committee publishes database on cards
1969 JCPDS incorporated; publishes the JCPDF
History
1938 Hanawalt paper on first database and search method
1941 ASTM committee publishes database on cards
1969 JCPDS incorporated; publishes the JCPDF
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
We use the Powder Diffraction File database (the PDF) and a search system
We use the Powder Diffraction File database (the PDF) and a search system
History
1938 Hanawalt paper on first database and search method
1941 ASTM committee publishes database on cards
1969 JCPDS incorporated; publishes the JCPDF1977 JCPDS became the International Centre for
Diffraction Data (ICDD) - currently publishing various databases, including the new PDF-4, with diffraction and structure data for >240,000 phases
History
1938 Hanawalt paper on first database and search method
1941 ASTM committee publishes database on cards
1969 JCPDS incorporated; publishes the JCPDF1977 JCPDS became the International Centre for
Diffraction Data (ICDD) - currently publishing various databases, including the new PDF-4, with diffraction and structure data for >240,000 phases
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
Make d, I list:
2.080 100 1 1.081 30 62.025 100 2 1.040 12 1.798 45 4 1.018 20 81.433 20 0.907 35 51.272 26 7 0.898 31.170 50 3 0.830 14
Make d, I list:
2.080 100 1 1.081 30 62.025 100 2 1.040 12 1.798 45 4 1.018 20 81.433 20 0.907 35 51.272 26 7 0.898 31.170 50 3 0.830 14
Do search/matchDo search/match
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
Example of page of search manual for Hanawalt manual search/matchExample of page of search manual for Hanawalt manual search/match
Powder diffraction - applicationsPowder diffraction - applications
Qualitative analysis - what IS this stuff?!! Qualitative analysis - what IS this stuff?!!
Make d, I list:
2.080 100 1 1.081 30 62.025 100 2 1.040 12 1.798 45 4 1.018 20 81.433 20 0.907 35 51.272 26 7 0.898 31.170 50 3 0.830 14
Make d, I list:
2.080 100 1 1.081 30 62.025 100 2 1.040 12 1.798 45 4 1.018 20 81.433 20 0.907 35 51.272 26 7 0.898 31.170 50 3 0.830 14
1 2 3 - no match1 2 4 - no match1 2 x - no match
1 2 3 - no match1 2 4 - no match1 2 x - no match
1 3 4 - no match1 3 5 - no match1 3 x - no match
1 3 4 - no match1 3 5 - no match1 3 x - no match
1 4 5 - no match1 4 6 - MATCH! 1 4 5 - no match1 4 6 - MATCH!
Do search/matchDo search/match
Powder diffraction - applicationsPowder diffraction - applications
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses
?
Powder diffraction - applicationsPowder diffraction - applications
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses
stress = modulus x strain = E
(Hooke's law)
stress = modulus x strain = E
(Hooke's law)
Powder diffraction - applicationsPowder diffraction - applications
Residual stress
Reflections shift position (d-values change under stress)
Residual stress
Reflections shift position (d-values change under stress)
Powder diffraction - applicationsPowder diffraction - applications
Residual stressesResidual stresses
Residual stress
Suppose isotropic solid loaded in uniaxial tension
Residual stress
Suppose isotropic solid loaded in uniaxial tension
Can measure change in interplanar spacing for planes reflecting as above
d = (d - do)/ do - this is the strain
Can measure change in interplanar spacing for planes reflecting as above
d = (d - do)/ do - this is the strain
= (1/E) (- ( + )) - is Poisson's ratio
= - (1/E) - so, can get stress
= (1/E) (- ( + )) - is Poisson's ratio
= - (1/E) - so, can get stress
Residual stress
Biaxial & triaxial stress states more complicated
Stress state resolved differently along different directions in sample, so peak shifts change w/ direction
Residual stress
Biaxial & triaxial stress states more complicated
Stress state resolved differently along different directions in sample, so peak shifts change w/ direction
= (1 + )/E sin2 /E)(+ = (1 + )/E sin2 /E)(+
Residual stress
Measurement procedure - classical technique - sin2
Residual stress
Measurement procedure - classical technique - sin2
Diffractometer must have two more rotations -
and Diffractometer must have two more rotations -
and
Residual stress
Measurement procedure - classical technique - sin2
Residual stress
Measurement procedure - classical technique - sin2
Residual stress
Measurement procedure - classical technique - sin2
Residual stress
Measurement procedure - classical technique - sin2
= (1 + )/E sin2 /E)(+ = (1 + )/E sin2 /E)(+
sin2
slopeslopeNeed E, -measure orcalculate
Need E, -measure orcalculate
Powder diffraction - applicationsPowder diffraction - applications
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses 7. Thin films
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses 7. Thin films
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Can rotatefilm and still get reflection
Powder diffraction - applicationsPowder diffraction - applications
Thin films Thin films
Powder diffraction - applicationsPowder diffraction - applications
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses 7. Thin films8. Crystallinity9. Studies of phase diagrams
A. Phase boundariesB. Solid solutionsC. Phase transitions
10. Studies of chemical reactions and identification of reaction products.
11. Determination of grain sizes.12. Preferred orientation in
polycrystalline bodies.13. Many more
1. Qualitative analysis2. Quantitative analysis 3. Crystal structure determination4. Crystallite size5. Microstrain 6. Residual macrostresses 7. Thin films8. Crystallinity9. Studies of phase diagrams
A. Phase boundariesB. Solid solutionsC. Phase transitions
10. Studies of chemical reactions and identification of reaction products.
11. Determination of grain sizes.12. Preferred orientation in
polycrystalline bodies.13. Many more
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