Att 1453297746917 15-6-2015final talk

Investigation on Microstructural Morphological Changes for Laser Irradiated Targets

Presented By:Tehseen Naz2012/II-M.phil-App-Phy-09

Supervised By:Prof. Dr. Anwar Latif

Department of physics, University of Engineering and Technology, Lahore.

ContentsObjectivesIntroduction ExperimentationCharacterization Results and DiscussionConclusionsApplicationsFuture work

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Objective

To Investigate the evolution of microstructures at the surface of nano second laser irradiated materials (Au, Al, Pt, Cu, Si, ABS).

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Introduction

Laser Matter InteractionInteraction of nanosecond laser pulse with matter causes: Absorption Thermal excitations Melting Microstructure growth Material ablation [1]

Figure 1: Interaction of ns laser pulse with matter.

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[1] Dolgaev, S.I. Kirichenko, N.A. Simakin, A.V. & G.A. Shafeev, “Laser assisted growth of microstructures on spatially confined substrates”, Applied Surface Science, 253, 7987 – 799 (2007).

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The interaction of nano-second laser with target material may produce [2]: Ripples Micro-droplets Cracks Crater Debris

Continued…

[2] D.Bauerle, Laser processing and chemistry 3rd Edition (Spring-Verlag Berlin, 2000) 215-217.

Experimentation

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Experimental Conditions

Targets

4 N pure fine polished Copper, aluminum, platinum, gold, Silicon (P-type) and Acrylonitrile butadiene styrene (ABS)

Nd:YAG Laser (1064nm,10mJ, 9-12ns, 1.1 MW)

IR- Transmission Lens Focal length (f ) = 8cm

Number of laser shots 25, 50, 75, 100, 125, 150Atmosphere Ambient air

Table 1: Experimental conditions for material irradiations.

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Figure 2: Schematic diagram of laser irradiation on targets.

Experimental Setup

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Nd:YAG Laser

Target Holder Stand

Target MaterialFocusing Lens

8cm

Focused Laser Beam

Characterization Technique

Optical Microscope(Olympus STM 6 with minimum read out of 0.1 µm)To explore the surface morphology of the targets.

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Results and Discussion

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Surface Morphology of Copper

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Figure 3: Optical micrographs of Cu irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.

Area of HAZ

(b)

Crater

Area of HAZ (a)

Crater Area of HAZ

(c)

Crater

Area of HAZ

(d)

Crater

Area of HAZ

(e)

Crater

Area of HAZ

(f)

Crater

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Sr no. No. of laser shots

Area of HAZ(μm2)

Crater depth(10-3) μ m

Crater area(10-12 m2)

Crater volume(10-21 m3)

Ablated mass(10-21

Kg)

1 25 177128.4 14.2 746.1996 10596.03 94940470

2 50 189253.4 26.6 933.8506 24840.43 222570216

3 75 224442.7 57.9 1683.995 97503.3 873629564

4 100 251736.4 67 1734.868 116236.2 1.041E+09

5 125 274585.5 78.9 2618.948 206635 1.851E+09

6 150 298685.9 90 3377.419 303967.7 2.724E+09

Continued…Table 2: HAZ, crater and ablated mass with increasing the number of laser shots.

Surface Morphology of Platinum

14Figure 4: Optical micrographs of Pt irradiated by (a) 25 (b) 50

(c) 75 (d) 100 (e) 125 (f) 150, laser shots.

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Area of HAZ(μm2)




Ablated mass(10-21

Kg)

1 25 4024.35 0.1 13568.38 1356.838 29104172

2 50 8420.511 2.4 17065.22 40956.52 878517342

3 75 8608.529 27 17932.73 484183.6 1.039E+10

4 100 9455.374 29.5 20756.38 612313.2 1.313E+10

5 125 10257.06 34 22735.52 773007.6 1.658E+10

6 150 11955.4 34.2 25850.42 884084.4 1.896E+10


Surface Morphology of Aluminum

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Figure 5: Optical micrographs of Al irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

Crater

CraterCraterCrater

Crater

(a) (b) (c)

(d) (e) (f)

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Area of HAZ(μm2)




Ablated mass(10-21

Kg)

1 25 30047.232 1063.263 2126.527 5741621.8

2 50 31267.194.8 1338.255 6423.624 17343785

3 75 32162.328.1 3634.566 29439.99 79487965

4 100 36335.529.4 4298.917 40409.82 109106502

5 125 50325.0714 4877.911 68290.75 184385025

6 150 51775.8630 6139.814 184194.4 497324896


Surface Morphology of Gold

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Figure 6: Optical micrographs of Au irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.

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Area of HAZ(μm2)




Ablated mass(10-21

Kg)

1 25 76574.96 22 0 0 0

2 50 169849.3 23 3649.418 83936.61 1.62E+09

3 75 178786.8 23.7 3895.001 92311.52 1.782E+09

4 100 182392 24.8 3983.038 98779.35 1.906E+09

5 125 190010.2 26.8 7839.187 210090.2 4.055E+09

6 150 191134.2 27 16619.69 448731.7 8.661E+09


Surface Morphology of Silicon

20Figure 7: Optical micrographs of Si irradiated by (a) 25 (b) 50

(c) 75 (d) 100 (e) 125 (f) 150, laser shots.

CraterReflectio

n patterns

(f)

Crater

Reflection

patterns

(e)

CraterCrater

Reflection patternsReflection

patterns

Crater

Reflection patterns

(d)

Crater

(a) (b) (c)

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Area of HAZ(μm2)




Ablated mass(10-21

Kg)

1 25 8420.511 6.7 10556.55 70728.89 164091019

2 50 15486.46 8 12264.06 98112.44 227620862

3 75 22826.04 18.4 12429.49 228702.7 530590182

4 100 30850.07 45 14377 646964.9 1.501E+09

5 125 34919.18 46 16472.49 757734.7 1.758E+09

6 150 44382.7 76 16981.73 1290612 2.994E+09


Surface Morphology of Acrylonitrile Butadiene Styrene (ABS) Polymer

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Figure 8: Optical micrographs of ABS irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.

(a)

(d)

(b) (c)

(e) (f)Crater

Crater

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

Area of HAZ

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Area of HAZ(μm2)




Ablated mass(10-21

Kg)

1 25 415.265 100 139.5522 13955.22 15071641

2 50 551.2663 220 10661.74 2345584 2.533E+09

3 75 5024 380 12266.78 4661377 5.034E+09

4 100 5182.227 530 14166.79 7508399 8.109E+09

5 125 5246.204 620 16809 10421579 1.126E+10

6 150 6148.316 630 23775 14978250 1.618E+10


Graphical analysis

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Comparison of HAZ of irradiated materials (Al, Au, Pt, Cu, Si, ABS)

25 Figure 9:A plot between area of HAZ and number of laser shots.

Comparative graph between crater depth and number of laser shots

26 Figure 10:A plot between crater depth and number of laser shots.

Comparative graph between crater area and number of laser shots

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Figure 11:A plot between crater area and number of laser shots.

Comparative graph between crater volume and number of laser shots

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Figure 12:A plot between crater volume and number of laser shots.

Comparative graph between ablated mass and number of laser shots

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Figure 13:A plot between ablated mass and number of laser shots.

Conclusions

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Microstructures (ripples, crater and micro droplets) are formed on irradiated surfaces.

All targets (Au, Al, Pt, Cu, Si, ABS) show a small crater formation but Au shows ripples with crater.

Area of HAZ, crater depth, crater area, crater volume and ablated mass increases by increasing number of laser shots.

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Sr.No.

Material Name

Trends

No. of laser

shots Vs area of

HAZ

No. of laser

shots Vs Crater depth

No. of laser shots Vs Crater

area

No. of laser

shots Vs Crater volume

No. of laser shots Vs Crater ablated mass

1 Au Exponential

Exponential

Exponential

Exponential

Boltzmann

2 Pt Exponential

Boltzmann

Polynomial Exponential

Exponential

3 Al Boltzmann Exponential

Exponential

Exponential

Exponential

4 Cu Linear Boltzmann

Exponential

Polynomial Boltzmann

5 Si Linear Exponential

Boltzmann Exponential

Exponential

6 ABS Boltzmann Polynomial

Exponential

Exponential

Exponential

Applications: Surface microstructuring is addressing significant

areas of research like• Ripple transmission grating [3]• Data storage devices• Corrosion protection [4]

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[3] H.Y. Zheng, T.T. Tan, W. Zhou, “Studies of KrF laser-induced long periodic structures on polyimide”, Optics and Lasers in Engineering, 47, 180–185 (2009).[4] L. Honga, Ruslia, X.C. Wangb, H.Y. Zhengb, H. Wanga, H.Y. Yuc, “Femtosecond laser fabrication of large-area periodic surface ripple structure on Si substrate”, Applied Surface Science , 297 , 134–138 (2014).

Future WorkComparison of electrical, optical, surface and morphological properties under the same conditions on different class of materials can be performed and the correlation may be formed between irradiated and un-irradiated materials by varying different parameters.

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Thank you !

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