Development and severe plastic deformation of novel hybrid MG based metal matrix composites

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DEVELOPMENT AND SEVERE PLASTIC DEFORMATION OF NOVEL HYBRID MG BASED METAL MATRIX

COMPOSITES

HARPRABHJOT SINGH

CENTRE FOR AUTOMOTIVE RESEARCH AND TRIBOLOGY (CART)

INDIAN INSTITUTE OF TECHNOLOGY, DELHI

OCTOBER 2021

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©Indian Institute of Technology Delhi (IITD), New Delhi, 2021

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DEVELOPMENT AND SEVERE PLASTIC DEFORMATION OF NOVEL HYBRID MG BASED METAL MATRIX

COMPOSITES

by

Harprabhjot Singh

Centre for Automotive Research and Tribology (CART)

Submitted

in the fulfillment of the requirements for the degree of Doctor of Philosophy to the

INDIAN INSTITUTE OF TECHNOLOGY DELHI

OCTOBER 2021

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___________________________________________________________________________

CERTIFICATE

This is to certify that the thesis titled, “Development and Severe Plastic Deformation of Novel Hybrid Mg based Metal Matrix Composites” being submitted by Harprabhjot Singh to the Indian Institute of Technology Delhi for the award of Doctor of Philosophy is a record of original bonafide research work carried out by him under my guidance and supervision. In my opinion, the thesis has reached the standard of fulfilling the requirements of all the regulations related to the degree. The research report and results presented in this thesis have not been submitted in part or in full, to any other university or institution for the award of any degree or diploma. I certify that he has pursued the prescribed course of research.

Dr. Deepak Kumar Associate Professor Date:

Place: New Delhi

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Acknowledgements

First of all, thank you God for helping throughout this journey. Although invisible, I could feel your presence during these challenging years. I am sure you were there otherwise it couldn’t be possible. I don’t have such a great wisdom that I can thank you with beautiful thoughts or writings. It was you who cared your servant and blessed him with wisdom, courage, determination, motivation and strength to work against all odds and achieve the goals. Again, tons of thanks.

Now, I would like to thank my supervisor Prof. Deepak Kumar. During this journey his motivation and support was always there. He was paragon of hard work and sincerity which always inspired me to excel. His extremely understand- ing and down to earth nature makes him unique and preferable boss. I enjoyed my research because of his freedom and support. I would like to thank my SRC mem- bers Prof. N. Tandon (CART), Prof. J. Bijwe (CART) and Prof. R.K. Pandey (Department of Mechanical Engineering) and Prof. Deepak Kumar (CART) for their helpful suggestions and comments during the progress report presentations.

I am extremely indebted to Prof. Harpreet Singh (IIT Ropar), Prof. J. Bijwe, Prof. Jayant Jain and Dr. Sanjeet Kumar for providing their instrumentation facilities whenever requested. Further, I owe gratitude to Central research facility (CRF) and Nano research facility (NRF) IIT Delhi, their staff and operators. My special thanks to Dr. Sanjeet Kumar (mentor/senior), Mr. Ajay Partap Singh Lodhi, Mr. Malkeet Singh Bajwa for their constant brotherly support during experimentation. They always motivated me to aim high. I could disturb them at

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any time for any support. They filled my research life with enthusiasm. Further, I would like to thank Dr. Aditya Gokhale and Dr. N. M. Chelliah for their special guidance.

I would take opportunity to thank Mr. Umesh and Ms. Megha Shree for their constant support and help during operation of instruments. I would like to give special thanks to Mr. Avi Gupta, Mr. Ankit, Mr. Abhijeet, Mr. Abhijith NV, Mr. Viney Saini, Mr. Navnath Kalel, Mr. Bhaskaran and Mr. Vanveer Chauhan for their support and filling my research life with essence of happiness.

I am highly obliged and like to give special thanks to Mr. Bharat Kumar for his special support during general/project related activities. I am thankful to MTech students Mr. Avinash, Mr. Parvinder, Mr. Ritesh and Mr. Vikas for creating light environment during lab activities. There was direct/indirect support from various laboratories. I would like to thank all researchers from Material Science lab, 3-D printing lab and Central Workshop. I would like to thank Mr. N. Ansari, Dr. Anuj, Dr. Gurminder Singh and Dr. Ajit Kumar in special. Beside them there are several people who directly or indirectly helped me during entire research work. I would like to thank them too.

I would like to thank laboratory staff who willingly devoted their time and supported with required instruments and necessary material. A special thanks to Mr. Subhash Chand (Metrology Lab), Mr. Avtar Singh, Mr. Mohan Singh, Mr. Sunil Kapoor, Mr. Ashok Kumar and Mr. Ram Kumar (IIT Ropar). I am thankful to office staff at CART, IIT Delhi for their constant involvement in managing our needs.

I wish to thank my best friends Mr. Harmeet Singh, Mr. Yadwinder Singh Joshan and Dr. Supreet Singh for their constant motivation and support during the whole journey. They were my heat sinks for all the worries. They motivated me to fight against all odds and put my efforts efficiently.

I owe eternal gratitude to my parents Sardar Jagmohan Singh and Sardarni Harprabhjot Singh @ CART, IIT Delhi Page ii

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Manjit Kaur, my sister Harleen Kaur and Brother-in-law Taranpreet Singh for their constant support in all required forms. Their inspiration, belief in me and thus encouragement lifted me through this phase of life. My special thanks to my fiance Dr. Sarabjot Kaur, because of her motivation I am able to timely submit my work. I would like to thank my cousins Japjot Singh and Harshdeep Kaur for filling my loneliness with their joyful presence during these year. At last lot of love to little Mansehaj Singh.

Harprabhjot Singh @ CART, IIT Delhi Page iii

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Abstract

Present work aims at developing Magnesium based metal matrix composites (MMC) through in-situ reinforcement. The in-situ generation of ceramic reinforcements during the casting of MMCs have wide advantages ranging from the generation to the better dispersion of ceramic particles and cost effectiveness. The in-situ generation of micro and nano particles may have better bonding with the matrix as compared to the ex-situ reinforcements.

With the aim to generate ceria (CeO2) and magnesia (MgO) through in-situ reaction, Ceric ammonium nitrate (CAN) is added to the Magnesium melt at tem- peratures of 670 ºC and 870 ºC. The developed MMCs are solution treated to get rid of intermetallic. The nature of the developed particles are explored with X-ray diffractometry (XRD) and Energy dispersion spectroscopy (EDS). The morphol- ogy and sizes of particles are keenly jotted using scanning electron microscope (SEM). The observations and analysis confirm the in-situ generation of CeO2, MgO and CeMg12 intermetallic phases in different types and sizes. The SEM and EDS analysis of the developed MMCs lead to categorization of particles and fea- tures into cauliflower structure, agglomerated nano ceramics, composite ceramic particles (CCP), uniformly distributed nano-ceramic particles, nano-pores and intermetallic. The presence of nano ceramic particles are further confirmed using transmission electron microscopy (TEM).

Mechanical responses of the developed MMCs are recorded in terms of hardness, compressive stress-strain curve and scratch resistance. The compression frac-

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tured surfaces are analyzed using SEM and scratched surface are analyzed using 3D optical profilometer to explore the deformation behavior. It is noted that the in-situ developed particles are responsible for the improved mechanical properties.

The preliminary wear response is recorded via scratched surfaces analysis using 3-D optical profilometer. Herewith, it is worth stating that it is possible to ma- nipulate the mechanical properties through controlling the in-situ reinforcement type and distribution. Structural clamping, riveting, and bolting, piston-cylinder assembly, valves, etc. are few areas where magnesium-based materials can be used and require to be wear resistant. To increase the possible applicability, the tribological responses of the developed MMCs are recorded using Tribometer for a range of load and speed under dry sliding contact condition. It is found that the wear and frictional response of the developed MMCs are much improved and attributed to the reinforcement type and distribution. Further, the electrochemical corrosion testing is performed on all the as-cast MMCs to comment on the corrosive degradation behavior.

The developed MMCs are subjected to severe plastic deformation (SPD) using press forging at 350 ºC. The evolution of textures during forging are evaluated using Electron backscatter diffraction (EBSD). The material selected from the central area and the peripheral area for the forged disk are subjected to mechanical testing (hardness, stress-strain behavior under compression and low amplitude wear response). The forged metal matrix composite (MMC) with the dominant presence of nano-ceramic particles outperformed during compression and wear tests. The dominance of basal texture at peripheral area explains the change in coefficient of friction (COF) and work hardening during compression.

The strengthening of the MMCs is accociated with the presence and generation of dislocations. A modified geometrically necessary dislocations (GNDs) generation model is proposed. It accommodates the mismatch of coefficient of thermal expansion (CTE) and elastic modulus between the matrix and the reinforcement.

Harprabhjot Singh @ CART, IIT Delhi Page v

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The interstitial prismatic loops are punched in spherical ceramic reinforced matrix. The developed model is verified using nano-indentation experimentation into the Mg matrix nano-composite (MMnC). This model is further used to establish the theoretical yield strength of the MMnCs and further verified with experimental results. Artificial neural network (ANN) are used to explore the correlation between microstructure and hardness of forged MMCs.

Harprabhjot Singh @ CART, IIT Delhi Page vi

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सार

वर्तमान कार्त का उद्देश्य इन-सीटू सुदृढ़ीकरण के माध्यम से मैग्नीशिर्म आधाररर् सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) शवकशसर् करना है। सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) की ढलाई के दौरान इन-सीटू उत्पादन (प्रशिर्ा शसरेशमक सुदृढ़ीकरण) से शसरेशमक कणोों के बेहर्र फैलाव और लागर् प्रभावी होने का व्यापक लाभ है। सूक्षम और नैनो कणोों की इन-सीटू प्रशिर्ा में उत्पादन, एक्स-सीटू सुदृढ़ीकरण की र्ुलना में मैशटिक्स के साथ बेहर्र ब ोंश ोंग वाला माना

जार्ा है।

इन-सीटू प्रशर्िीर्ा के माध्यम से सेररर्म ऑक्साइ (CeO2) एवों मैग्नीशिर्म ऑक्साइ (MgO) के उत्पादन के उद्देश्य से, ६७० श ग्री सेंटीग्रेट र्था ८७० श ग्री सेंटीग्रेट र्ापमान पर द्रशवर् मैग्नीशिर्म के साथ सेररक अमोशनर्म नाइटिेट (CAN) को

शमलार्ा जार्ा है। शवकशसर् सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) को इोंटरमेटेशलक (CeMg12) रशहर् होने के

शलए सोल्युिन िोशधर् होर्े हैं। शवकशसर् कणोों की प्रकृशर् का एक्स-रे श फ्रेक्टोमेटिी (XRD) और एनशजत श स्पितन स्पेक्टिोस्कोपी

(EDS) से पर्ा लगार्ा जार्ा है। कणोों की सोंरचना एवों आकार को स्कैशनोंग इलेक्टि न माइिोस्कोप (SEM) के इस्तेमाल करर्े

हुए गौर से शलखा जार्ा है। प्रेक्षणोों और शवश्लेषणोों ने शवशभन्न प्रकार एवों आकार के CeO2, MgO एवों CeMg12 इन-सीटू

उत्पादन की पुशि की है। शवकशसर् सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) के एसईएम एवों ई ीएस शवश्लेषण, इन कणोों का फूलगोभी की सोंरचना, पुोंशजर् नैनो सेरमीक, शमशिर् सेरमीक कणोों (CCP), समान रूप से शवर्ररर् नैनो-सेरमीक कणोों, नैनो-शिद्र एवों इोंटरमेटाशलक में वशगतकरण करर्े है। आगे नैनो सेरमीक कणोों की उपम्मथथर्ी की पुशि टिाोंिशमिन इलेक्टि न माइिोस्कोपी (TEM) द्वारा भी की गई।

शवकशसर् सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) के र्ाोंशिक प्रशर्शिर्ाओों को कठोरर्ा, सोंपीश र् स्ट्िैस-स्ट्िेन कवत एवों स्क्रैच प्रशर्रोध के सोंदभत में दजत शकर्ा गर्ा है। शवरूपण व्यवहार का पर्ा लगाने के शलए सोंपीड़न खोंश र् सर्होों का

शवश्लेषण एसईएम का उपर्ोग करर्े हुए एवों खरोोंचे गए सर्ह का शवश्लेषण 3- ी ऑशिकल प्रोफ़ाइलोमीटर का प्रर्ोग करर्े

हुए शकर्ा गर्ा। र्ह देखा गर्ा शक इन-सीटू शवकशसर् कण बेहर्र र्ाोंशिक गुणोों के शलए शजिेदार हैं। 3- ी ऑशिकल प्रोफ़ाइलोमीटर के प्रर्ोग से खरोोंचे गए सर्ह के शवश्लेषण द्वारा प्रारम्मिक टूट-फूट (Wear) प्रशर्शिर्ा को दजत शकर्ा गर्ा है।

साथ ही, र्ह कथनीर् है शक इन-सीटू सुदृढ़ीकरण प्रकार और शवर्रण को शनर्ोंशिर् करके र्ाोंशिक गुणोों में हेरफेर करना सोंभव है। सोंरचनात्मक क्लैम्मम्पोंग, राइवेशटोंग एवों बोम्मटोंग, शपस्ट्न-शसशलों र असेंबली, वाल्व्स आशद कुि ऐसे क्षेि हैं जहाों मैग्नीशिर्म आधाररर् पदाथत का प्रर्ोग शकर्ा जा सकर्ा है एवों टूट-फूट (Wear) रशहर् होने के शलए आवश्यक है। सोंभाशवर् प्रर्ोज्यर्ा को

बढ़ाने के शलए, शवकशसर् एमएमसी की टिाईबोलोशजकल प्रशर्शिर्ाओों को, टिाईबोशमटर के प्रर्ोग से सुखी स्लाइश ोंग सोंपकत

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म्मथथशर् में लो और गशर् की एक सीमा र्क दजत शकर्ा गर्ा। र्ह पार्ा गर्ा शक शवकशसर् एमएमसी के वेर्र एवों घषतण प्रशर्शिर्ाओों में काफी सुधार हुआ और सुदृढ़ीकरण प्रकार एवों शवर्रण में सहर्ोगी हुआ। साथ ही, सभी सम्मिशिर् कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट) पर सोंक्षारक अवनशर् व्यवहार पर शटप्पणी के शलए इलेक्टिोकेशमकल जोंग परीक्षण शकर्ा गर्ा।

शवकशसर् एमएमसी को ३५० श ग्री र्ापमान पर दाब ढलाई (press forging) का उपर्ोग करने पर कठोर प्लाम्मस्ट्क शवरूपण (SPD) होर्ा है। ढलाई के दौरान बनावट के शवकास का मूल्याोंकन इलेक्टि न बैकस्कैटर शववर्तन (EBSD) का उपर्ोग करके

शकर्ा गर्ा है। ढाले गए (फ़ोजत) श स्क के शलएकेंद्रीय क्षेि और पररधीर् क्षेि से चर्शनर् सामाग्री का र्ाोंशिक परीक्षण (कठोरर्ा, सोंपीड़न के र्हर् र्नाव-म्मखोंचाव व्यवहार और कम आर्ाम पर टूट-फूट प्रशर्िीर्ा) ककया गया। कम्पोजीट धार्ु (मेटल मैशटिक्स कम्पोजीट), सोंपीड़न और टूट-फूट परीक्षण के दौरान नैनो-सेरमीक कणोों की प्रबल उपम्मथथर्ी के साथ बेहर्र प्रदितन करर्ा

है। पररधीर् क्षेि में बेसल बनावट का प्रभुत्व घषतण के गुणाोंक में पररवर्तन और सोंपीड़न के दौरान सख्त होने की व्याख्या करर्ा

है।

सम्मिकित कम्पोजीट धातु (मेटल मैकटिक्स कम्पोजीट) की मजबूती किसलोकेशन की उपम्मथिती और उत्पकत से जुड़ा है। एक संशोकधत ज्याकमतीय रूप से आवश्यक किसलोकेशन उत्पादन मॉिल प्रस्ताकवत है। यह मैकटिक्स और कणोों के बीच ताप कवस्तार प्रसार गुणांक (CTE) और लोचदार मापांक के बेमेल को समायोकजत करता है। गोलाकार सेरेकमक कण मैकटिक्स में

अंतरालीय कप्रज्मीय लूप घुसाए हुए होते हैं। कवककसत मॉिल एमजी मैकटिक्स में नैनो-इंिेंटेशन परीक्षण का प्रयोग कर सत्याकपत है। आगे इस मॉिल का उपयोग सम्मिकित कम्पोजीट धातु (मेटल मैकटिक्स कम्पोजीट) के सैद्धाम्मिक नम्य होने की

क्षमता/शम्मि को थिाकपत करने के कलए ककया गया है तिा साि ही यह प्रयोगात्मक पररणामों के साि सत्याकपत है। गकित सम्मिकित कम्पोजीट धातु (मेटल मैकटिक्स कम्पोजीट) की सूक्ष्म संरचना और कठोरता के बीच संबंध का पता लगाने के कलए कृकिम तंकिका नेटवकक (ANN) का प्रयोग ककया गया है।

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List of Figures

1.1 Production history of Mg and Al alloys in China [14] . . . 3

1.2 Price history of Mg and Al from 2004 till 2014 [14] . . . 4

1.3 Crystallographic planes in Mg responsible for deformation and twin- ning [74] . . . 16

1.4 The problem identified, possible solutions and research objectives 21 1.5 Graphical representation of manufacturing process and characteri- zation carried out on forged samples. . . 24

2.1 Bottom pouring inert gas stir casting furnace at Bharat Forge, Pune. 28 2.2 Mg-Ce phase diagram [82] . . . 29

2.3 High temperature hydraulic press. . . 30

2.4 Olympus optical microscope . . . 31

2.5 Hardness testing setup . . . 34

2.6 Universal tribometer . . . 35

2.7 Tribometer in pin-on-disk configuration . . . 38

2.8 High frequency reciprocating rig [83]. . . 39

2.9 Photographic view of electrochemical corrosion test rig . . . 39

3.1 Optical micrographs of (a) as-cast Mg, (b) MMC casted at 870 ºC (C92), (c) MMC casted at 670 ºC (C91) and (d) solution treated C91 MMC . . . 42

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LIST OF FIGURES

3.2 XRD spectra for MMCs cast at 870 ºC (C92, red), MMC cast at 670 ºC (C91, black) and solution treated C91 MMC, blue. . . 43 3.3 (a) SEM micrograph and (b-f) corresponding X-ray mapping of

C91 MMC; with special attention to cerium based intermetallic. . 44 3.4 (a) SEM micrograph and (b-f) corresponding X-ray mapping of

CS91 MMC with special attention to ceria particles. . . 45 3.5 SEM micrographs of C91MMC, depicting the nano/submicron par-

ticles (a) clusters and (b) high resolution of the small area (16000x). 46 3.6 SEM and corresponding X-ray mapping of CS91 MMC; depicting

cauliflower structure of MgO. . . 47 3.7 SEM micrographs of C91 MMC depicting the presence of nanopar-

ticles, (a) microscopic view and (b) high resolution micrograph of the specific area. . . 48 3.8 SEM and X-ray mapping of C91 MMC; depicting indent mark on

the continuous ceramic particle (CCP). . . 49 3.9 SEM micrograph of C92 MMC, (a) and (b) are at different locations. 50 3.10 Vickers hardness of as-cast Mg, C92, C91, CS91 MMCs. . . 51 3.11 SEM micrographs of indentation mark on the cluster of submicron/nano-

particles in C91 MMC, at different resolutions depicting the presence of nano-particles. . . 52 3.12 3D-optical profilometer images for scratched surfaces of (a) as-cast

Mg, (b) C92, (c) C91 and (d) CS91 MMCs . . . 53 3.13 Representative line scan of the scratched mark on as-cast Mg, C92,

C91, CS91 MMCs along with traction force. Recorded using 3-D optical profilometer. . . 54 3.14 Mapping of scratch hardness and wear volume during recording the

scratch resistance of as-cast Mg, C92, C91, CS91 MMCs. . . 55

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LIST OF FIGURES

3.15 Stress-strain behavior during compression test of as-cast Mg, C92, C91, CS91 MMCs samples (strain rate of 1.39 x 10-3 s-1 ) . . . . 56 3.16 SEM micrograph of failed surfaces during compression test for as-

cast Mg (a-c), C91 (d-f), CS91 (g-h), C92 (i-k). . . 58 3.17 Individual strengthening contribution of Load Transfer, Taylor Strength-

ening, Orowan Strengthening and Hall-Petch Strengthening in the strengthening of C91, C92, CS91 MMCs. . . 60 3.18 Experimental yield strength and yield strength calculated through

Summation model, Zhang and Chen model and modified Clyne model for C91, C92, CS91 MMCs. . . 61 4.1 Optical micrographs of (a) as-cast Mg (b) C31 MMC (c) C61 MMC

(d) C91 MMC . . . 64 4.2 XRD pattern of as-cast Mg, C31 MMC, C61 MMC, C91 MMC . . 65 4.3 Summary of different characteristics; Overview, Nano-porosity, Ag-

glomerates, Cauliflower particles, Continous ceramic particles (CCP), Intermetallic, and Nanoparticles recorded for C31, C61, C91 MMCs. 68 4.4 Variation of Vickers hardness for as-cast Mg, C31, C61, C91 MMCs. 69 4.5 SEM micrographs and corresponding X-ray mapping of the indent

on composite ceramic particle present in C91 MMC . . . 70 4.6 (a) SEM micrographs and (b-d) X-ray mapping of the indent on a

cluster of particles (e-f) higher resolution image of indent. . . 71 4.7 Compression behavior of as-cast Mg, C91, C61, C31 MMCs . . . . 72 4.8 Fractured surface of (a-b) as-cast Mg, (c-d) C31, (e-f) C61, (g-h)

C91MMC . . . 72 4.9 Three-dimensional micrograph of scratched surfaces: (a) as-cast

Mg (b) C31 (c) C61 (d) C91 MMC . . . 73

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LIST OF FIGURES

4.10 Scratch hardness and wear volume of as-cast Mg, C31, C61, C91 MMC . . . 74 4.11 Contribution of various strengthening mechanisms for C31, C61,

C91 MMCs . . . 77 4.12 Comparison of various numerical models of yield strength for C31,

C61, and C91 MMCs . . . 78 5.1 Specific wear rate of Mg and MMCs during pin-on-disk test at

different load and sliding conditions. . . 81 5.2 (a) Variation of COF with sliding distance (b) Effect of different

tribological conditions on average COF of Mg and MMCs . . . 83 5.3 Post experimental macroscopic appearance of the tribo disks slid

under test conditions of 22, 25, 42, 45 for pure Mg. . . 85 5.4 SEM micrographs and corresponding X-ray mapping of tribo disk

(a) M21 (b) 921 (c) M41 (d) 941 (e) M22 (f) 922 (g) M42 (h) 942 (i) M25 (j) 925 (k) M45 (l) 945 . . . 86 5.5 SEM micrographs of wear track on Mg and different MMcs for (a)

M21 (b) 921 (c) M41 (d) 941 (e) M22 (f) 922 (g) M42 (h) 942 (i) M25 (j) 925 (k) M45 (l) 945, conditions. . . 89 5.6 Taffel plot for the as-cast Mg and MMCs. . . 90 5.7 SEM micrographs of corroded surfaces of (a) as-cast Mg (b) C31

(c) C61 (d) C91 MMCs . . . 90 6.1 SEM micrographs of as-cast (a) C91, (b) C61, (c) C31 MMCs and

forged (d) C91F, (e) C61F, (f) C31F MMCs . . . 93 6.2 XRD analysis of as-cast C31, C61 and C91 MMCs . . . 94 6.3 TEM micrographs of C61 MMC showing ceramic particles as dark

areas. . . 95

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LIST OF FIGURES

6.4 Variation of hardness for different forged MMCs; C - central area and P -peripheral area. . . 95 6.5 Compressive stress-strain curve for different forged MMCs; C - cen-

tral area and P -peripheral area. . . 96 6.6 Fractographs, collected using SEM, of failed surfaces of forged Mg

and MMCs: (a) MgF (b) C31F (c) C61F (d) C91F. . . 97 6.7 Macrographs of failed samples under compression test . . . 98 6.8 EBSD analysis indicating (a) band contrast (BC) map for C31F_C

(b) inverse pole figure (IPF) map for C31F_C (c) local angle mis- orientation (LAM) map for C31F_C (d) BC map for C31F_P (e) IPF map for C31F_P (f) LAM map for C31F_P. . . 99 6.9 EBSD analysis indicating (a) BC map for C61F_C (b) IPF map

for C61F_C (c) LAM map for C61F_C (d) BC map for C61F_P (e) IPF map for C61F_P (f) LAM map for C61F_P. . . 100 6.10 Wear micrographs of forged MMCs; C - central area and P -peripheral

area. . . 101 6.11 Taffel plot for forged MMCs (a) center (b) periphery . . . 103 6.12 SEM micrographs of the corroded surfaces of (a) MgF_C (b) C31F_C

(c) C61F_C (d) C91F_C MMCs near central region . . . 108 6.13 SEM micrographs of the corroded surfaces of (a) MgF_P (b) C31F_P

(c) C61F_P (d) C91F_P MMCs near peripheral region . . . 109 7.1 Schematic representation of; (a) deformation of matrix in the ab-

sence of spherical particle under loaded condition and (b) generation of dislocation loops under strained condition in the presence of reinforcement. . . 111 7.2 SEM micrographs showing the microstructure of hybrid MMC in

nano ceramic particles rich area. . . 114

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LIST OF FIGURES

7.3 Nano-indentation; (a) SEM micrograph of indentation mark in nano-ceramic particles rich area and (b) P-h curve for Mg based hybrid MMC in the same area. . . 115 7.4 Individual strengthening effects of various models contributing to

the enhancement of the yield strength. . . 116 7.5 Approach used to establish structure property correlation through

AI. . . 117 7.6 SEM micrographs of indents on as-cast MMCs . . . 118 7.6 SEM micrographs of indents on as-cast MMCs (continued) . . . . 119 7.6 SEM micrographs of indents on as-cast MMCs (continued) . . . . 120 7.7 Experimentally obtained yield strength and predicted yield strength

through AI corresponding to test data of as-cast MMCs. . . 123 7.8 SEM micrographs of indents on forged MMCs . . . 124 7.8 SEM micrographs of indents on forged MMCs (continued) . . . . 125 7.8 SEM micrographs of indents on forged MMCs (continued) . . . . 126 7.9 Experimentally obtained yield strength and predicted yield strength

through AI corresponding to test data of forged MMCs. . . 128

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List of Tables

1.1 Empirical formulas for calculating individual strengthening effects for different strengthening mechanisms [43,44] . . . 13 3.1 Particle type, size, volumetric distribution in different analytes. . 59 4.1 Particle type, size, volumetric distribution in MMCs. C91 C61 C31 78 5.1 Nomenclature of the analytes under different test conditions. . . . 81 5.2 Corrosion rate (mm/year) and Corrosion potential (V) for the as-

cast MMCs and Mg. . . 89 6.1 Corrosion rate and corrosion potential of forged MMCs at center

and periphery . . . 102 7.1 Corrosion rate and corrosion potential of forged MMCs at center

and periphery . . . 114 7.2 Volume fractions of different reinforcements of as-cast MMCs cor-

responding to the Figure 7.6 and their corresponding hardness. . . 122 7.3 Volume fractions of different reinforcements of forged MMCs cor-

responding to the Figure 7.8 and their corresponding hardness. . 127

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Acronyms and Notations

MMC Metal matrix composites MMC CAN Ceric ammonium nitrate CAN CeO2 Ceria

MgO Magnesia

XRD X-raydiffractometry

EDS Energy dispersion spectroscopy SEM Scanning electron microscope CCP Composite ceramic particles TEM Transmission electron microscopy SPD Severe plastic deformation

EBSD Electron backscatter diffraction COF Coefficient of friction

GNDs Geometrically necessary dislocations CTE Coefficient of thermal expansion MMnC Metal matrix nano-composite ANN Artificial neural network

CRSS Critical resolved shear stress

∆α Relative thermal expansion coefficient

∆t Temperature change

_p Strain

K_HP Hall Petch constant

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LIST OF TABLES

D_f Final grain size D_o Initial grain size

S_ym Yield strength of matrix V_p Volume fraction of particles

k Constant

G Shear strength of matrix b burgers vector

d_p particle size

M Taylor constant for Magnesium

Harprabhjot Singh @ CART, IIT Delhi Page xix

Development and severe plastic deformation of novel hybrid MG based metal matrix composites

DEVELOPMENT AND SEVERE PLASTIC DEFORMATION OF NOVEL HYBRID MG BASED METAL MATRIX

COMPOSITES

HARPRABHJOT SINGH

CENTRE FOR AUTOMOTIVE RESEARCH AND TRIBOLOGY (CART)

INDIAN INSTITUTE OF TECHNOLOGY, DELHI

OCTOBER 2021

DEVELOPMENT AND SEVERE PLASTIC DEFORMATION OF NOVEL HYBRID MG BASED METAL MATRIX

COMPOSITES

INDIAN INSTITUTE OF TECHNOLOGY DELHI

OCTOBER 2021

CERTIFICATE

Acknowledgements

Abstract

सार

Contents

List of Figures

List of Tables

Acronyms and Notations