The document summarizes a final year presentation project on characterizing the microstructure, mechanical properties, and corrosion behavior of laser beam welded Inconel 625 alloy samples. The objectives were to study and characterize the properties of laser beam welded Inconel 625 plates and determine if they are suitable for engineering applications. Samples were laser beam welded and then underwent mechanical testing including tensile and microhardness tests. Characterization techniques like optical microscopy, XRD and corrosion testing were also performed. The fusion zone was found to be the hardest zone and single notch samples exhibited remarkable strength compared to double notch and literature samples. Overall, the study characterized the microstructure, properties and corrosion behavior of laser beam welded Incon

1. Characterization of microstructure, mechanical
properties and corrosion behavior of laser beam
welded Inconel 625 weldments
- Final Year Presentation -
Advisor: Dr. Fahd Nawaz
Co-advisor: Engr. Asim Iltaf
FACULTY OF MATERIALS AND CHEMICAL ENGINEERING
Group Members:
Haris Ahmed 2017141
M.Haris Saeed 2017210
Yasir Iftakhar 2017503

2. Inconel 625
Inconel is a nickel-based
super alloy
Excellent oxidation
resistance at elevated
temperatures
Ability to withstand extreme
heat levels
Elevated mechanical
properties

3. 3
Aims/
Objectives
To Study and characterize the properties of similar
Laser beam welded two plates of Inconel 625
To conclude whether these properties are suitable and
effective for the engineering applications such as Aircraft
industries.

4. PROJECT PROGRESS
Inconel 625 samples
(As received)
LB Welding
Mechanical
Testing
Characterization
Techniques
Tensile Test
Optical Microscopy
Micro-
hardness
Measurement
XRD
Gamry
Potentiostate
Wire cutting

5. LASER BEAM WELDING
5
The welding parameters are:
• Welding Current (180 Amps)
• Pulse Width (10ms)
• Pulse Frequency (10)
• Welding Speed (300mm/min)
• CO2 Pulsed Laser

6. WIRE CUTTING
6

7. TENSILE TESTING
7
• Strain Rate 2.5 mm/min
• 0.2% Yield Strength
• 2 Single notch and 2 Double notch used
• Single notch having remarkable strength
• Fusion Zone stronger than Base Metal
Sample Name YS
(MPa)
UTS
(MPa)
Fracture Strength
(MPa)
Single notch 1 263 370 243
Single notch 2 262 383 221
Double notch 1 969 1771 775
Double notch 2 1012 1881 1016
Literature sample 598 971 863

8. MICRO-STRUCTURES
• The Base metal contains an equiaxed grain microstructure and α grains
are surrounded by the β matrix
• As we move towards the Heat affected zone (HAZ), the previous grains
grew larger in size and we can clearly see the BM-HAZ interface and a
transition is occurring
8

9. • In the fusion zone, we can see that the grains have grown much larger
than the heat affected zone
• Parallel striations
• Heat Retention and Grain size growth
9

10. MICRO-HARDNESS
• 200 gram load applied in all three zones
• Hardness Profile
• Micro-hardness increases towards fusion
zone and decreases away from it
• Peaks of low and hard hardness values is due
to several hard and soft areas
• Fusion zone is the hardest zone, followed by Heat Affected and Base
metal
10

11. X-Ray Diffraction
• some dominating peaks of Ni-Cr solid solution Ɣ-phase
• Presence of carbides NbC and Cr3C2
• The Ni8Nb can also be seen in the spectrum
• impact on the overall alloys tensile strength
11

12. 12

13. Corrosion Tests
• Tafel polarization, Electrochemical Impedance spectroscopy (EIS) and
Cyclic polarization curves
• Ecorr and Current is -344.7mV and 2.847µA, dimensions of sample
were (2x2) cm so the Icorr is 0.71175 µA/cm2
13

14. • EIS graph where the double passivation is calculated using by making
the equivalent electric circuit
• no oxide layer formed on the surface of the sample and therefore no
passivation occurred
• But lack of stirring mechanism during testing resulted in less corrosion
of the sample
14

15. 15
• the cyclic polarization curve, where we calculate area under the curve
in order to determine the susceptibility of the sample to corrosion
• only indicate that the sample is simply more prone to corrosion

16. 16
REFERENCES
 Mortezaie A, Shamanian M (2014) An assessment of microstructure, mechanical properties and
corrosion resistance of dissimilar welds between Inconel 718 and 310S austenitic stainless steel. Int J
Pres Ves Pip 116:37–46. https://doi.org/10.1016/j.ijpvp.2014.01.002
 Hirose A, Sakata K, Kobayashi KF (1998) Microstructure and mechanical properties of laser beam
welded Inconel 718. Int J Mater Prod Technol 13(1–2):28–44
 Casalino G, Mortello M (2016) A FEM model to study the fiber laser welding of Ti6Al4V thin sheet. Int J
Adv Manuf Technol 85:1339–1346
 Singh BM, Rokne J, Dhaliwal RS (2008) Vibrations of a solid sphere or shell of functionally graded
materials. Eur J Mech A-Solid 27(3):460–468

17. THANK YOU