-Carried out the characterization of material followed by axial deformation and determined the corresponding strain rates with 99% accuracy -Calculated the strain rate at different length scales using  X-Ray Diffraction  Electron Back Scattering  Digital Image Correlation -Observed the moving grain boundary behavior and twinning upon axial deformation of galvanized steel at different deformation conditions

1. MSE 313 A
Pseudo-InSitu Testing and characterizationof
Galvanizedsteel
GROUP A1 (MONDAY)
Prof. Nilesh Prakash Gurao
Abhishek Arya
Aditya Choudhary
Aditya Pratap Singh
: 12019
; 12044
: 12048
Aditya Shankar
Akash Bajaj
Alkesh Sinha
: 12052
: 12060
: 12078

2. OUTLINE
• Introduction
• Objective
• Theory
• Characterization Tools
• Tensile Test
• XRD
• Fracture Analysis
• Results
• Conclusions
• Acknowledgements

3. Introduction
• The Latin phrase “in-situ” means “on site”. Thus, in-situ testing
of materials is testing materials and observing them
simultaneously.
• Galvanized Steel is steel obtained after coating it with zinc
which prevents further corrosion.
• Combination of high strength and formability is an important
feature of zinc-coated galvanized steels utilized in buildings.
• Thus, mechanical testing to study their deformation
mechanism is very important.

4. Objective
• Measuring strain evolution at different length scales by in-situ
testing.
• To investigate the fracture and damage mechanism of
galvanized steel and its quantitative analysis based on loading
conditions

5. Theory
• Zinc-based coatings are widely used for protection against corrosion of steel-
sheet products
• HCP metals have limited number of slip systems, so they deform by both
slipping and twinning mechanism.
• For typical hcp metals, the primary systems are:
– Basal slip {0001}<1210>
– Prismatic slip {1010}<1210>
– Pyramidal twins {1011}

6. Theory
• Fracture Mechanism
• An Intergranular fracture is a fracture that follows the grains of the material. If the
material has multiple lattice organizations, when one lattice ends and another
begins, the fracture changes direction to follow the new grain
• A Transgranular fracture is a fracture that follows the edges of lattices in
a granular material, ignoring the grains in the individual lattices
Intergranular Fracture TransGranular Fracture

7. SPANGLES

8. Characterization Tools
• Initial (Undeformed) and Final (Deformed) characterization
of the zinc coated steel using the following tools : -
• Uni-axial Tensile Loading
• Optical Microscopy
• XRD analysis
• Tensile Test with video recording and subsequent
fracture analysis

9. Tensile Test
• Tensile Specimen
• All dimensions are in mm
0 100 200 300 400 500 600
0
100
200
300
400
500
600
700
N
Elongation (mm x 10-2
)
Load vs Elongation Curve
0.00 0.05 0.10 0.15 0.20
-20
0
20
40
60
80
100
120
140
160
180
TrueStress
F/mm-2 Strain)
True Stress Vs True Strain Curve)
True Stress vs True Strain

10. XRD ANALYSIS
UNDEFORMED DEFORMED
002

11. XRD Analysis
• Mass absorption and layer geometry influence the signal intensity.
• No significant peak broadening
• Crystallite size greater than 100 nm
• Micro strain evolved negligible.
• Considerable peak shift
• Macro strain evolved significant
• Change in the lattice spacing will be
• Accompanied by a change in the angle between the incident ray and the
scattering plane
• A change in the hydrostatic strain exhibits itself as a shift in radial peak
positions.
• While variations in deviatoric strain can produce both radial and
azimuthal motion of peak positions.
• Hint of texture evolution: (100) & (101) peaks gained more prominence
Intensity of (002) peak reduced

12. STRAIN CALCULATION
Strain formula
crystallite size formula
Where Dp = Average Crystallite size,
β = Line broadening in radians.
θ = Bragg angle.
λ = X-ray wavelength
Parameters Undeformed Deformed
I002/I100 2.58 0.29
I002/I101 1.48 0.52
Crystallite Size 175.78nm 55.33nm
Micro Strain .0006 .0019
Macro Strain -
Δd/d
0
=−cotθ
0
Δθ=𝜀
hkl

13. FRACTURE ANALYSIS

14. Results• Orientation Coefficient Calculations
• Inference 1 : The non-deformed sample had a strong basal orientation
• Inference 2 : Basal orientation in the deformed samples decreased
• Inference 3 : Prismatic orientation started developing after deformation
• Inference 4 : The shift towards prismatic orientation was more prominent in
higher spangle sizes

15. Results
Appearance of Twins after
deformation
• Prior to deformation, samples
show a very strong basal
texture
• During deformation,
contractional twinning takes
place in the grains
• It generates a crystal rotation in
those regions causing prismatic
orientation to increase
• Fracture Analysis also depicts
intergranular cracking during
tension

16. Conclusions
• Hot-dip galvanized process inherently generates a strong basal
texture
• It turns towards prismatic textures because of deformation
• The deformation modes working in the zinc coating are mainly
twinning and slipping according to the prismatic systems
• Tension produces great intergranular cracking

17. Acknowledgements
• Dr. N.P. Gurao
• Mr. K. Chandrashekhar
• Krishna Petiwala Rawatpur (Kanhaiya)