Ehab Salama

Abstract

Research on Al-CNT composites is in strong demand due to their high specific properties, and their potential applications in many advanced areas like in automotive and aerospace industries. In the current study, tensile and fracture properties of aluminum-multiwall carbon nanotube composites (Al-CNT) were investigated. A 99.7% pure AlPOCO® aluminum powder having an average particle size of 75 microns, in addition to 70-90% pure Elicarb® multi-walled carbon nanotubes having 10-12 nm average diameter were utilized in the synthesis of single and dual matrix multiwall carbon nanotube reinforced aluminum composites. Single matrix Al-CNT composite powders with 1, 2, 2.5, 5 wt.% CNT fraction were synthesized using the high energy ball milling (HEBM) of Al and CNT powders for 1 hour at 400 rpm. Dual matrix Al-CNT composites of 1, and 2.5 wt.% CNT loadings were synthesized from 1:1 mixtures of single matrix Al-2 and 5 wt.% CNT composite powders, respectively, and unmilled aluminum powders using HEBM for 1 hour at 400 rpm. Composite powders of different compositions were consolidated using conventional powder metallurgy processes; this included cold compaction, hot compaction, sintering, and hot extrusion processes in order to obtain high density compacts of the Al-CNT composites that are appropriate for different mechanical testing procedures. Several mechanical testing and characterization methods were applied to closely explore the mechanical properties and structural features of the Al-CNT composites. This included mechanical tension, and Elastic plane-strain fracture toughness tests as well as scanning electron microscopy, x-ray diffraction, Nanoindentation, and Raman spectroscopy. Improvements in composite properties by tailoring the synthesis parameters as well as structural related information revealed by different testing and characterization methods are reported later in this study. It was concluded that the addition of CNT to the Aluminum matrix had a positive impact on the material strength with a corresponding loss in ductility. The study also showed that the dual matrix principle could positively retain some of the material ductility when employing the right milling conditions and mixing ratios. On the other hand, no significant influences of CNT on the elastic plane strain fracture toughness of aluminum was observed. Instead, transition of the material fracture behavior to a less ductile manner was observed.

Department

Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Graduation Date

6-1-2013

Submission Date

April 2013

First Advisor

Esawi, Amal

Committee Member 1

Farag, Mahmoud

Committee Member 2

Wifif, Abdulla

Extent

159 p.

Document Type

Master's Thesis

Library of Congress Subject Heading 1

Composite materials.

Library of Congress Subject Heading 2

Steel-aluminum alloys.

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

Actually no words could express how grateful I am at this moment to all people who contributed to this work even with a small piece of advice. First of all, I would like to deeply thank my outstanding advisor Dr. Amal Esawi for her precious contributions to this work. Actually this work wouldn't have appeared in a complete form except for her scientific and technical inputs, persol encouragement, endless effort, persistence, and continuous support during different phases of this study. I would like to appreciate the fincial support of the Yousef Jameel Science and Technology research Center for funding all different phases of this research and for providing the adequate lab testing and characterization facilities. I am greatly thankful to the entire center's staff for offering continuous fincial and technical support. I am very thankful to Dr. Ehab Abdel Rahman, director of the YJ-STRC and to Dr. Sherif Sedky, the former director of the YJ-STRC for their encouragement and support. I am deeply thankful to the mechanical engineering department at AUC staff for their help during the processing and testing phases of this research. I would like to convey my gratitude to the mechanical engineering department chair Dr. Salah El-Haggar and the assistant to chair Mrs. Magda El-mahalwy, also for the department secretaries Ms. Ami and Mrs. Yathrib for providing proper guidance and help in many situations during my study at AUC. I am very thankful for Lab and workshop engineers Zakarya, and Khaled Iraqi for their tremendous help. I would like also to thank Mr.Hussien and Mr. Abo elkasem for their help in the sample preparation and testing activities. I would like also to convey my deep appreciation to Dr. Chahiz Saleh, professor of mechanical design at Cairo University, for her generous support in the fracture toughness part of this work. Dr. Chahiz has provided a complete fracture toughness testing environment including her valuable persol help and her lab testing facilities. I would like also to acknowledge the valuable help and support from my friend engineers and scientists Ahmed Salem, Ahmed Elghazaly, Ahmed Abdel Gawwad, Kamel Abdel Moneam, Haytham El-Gazzar, Ahmed Waleed, Mohy-eldin Safwat, Abdel Hamid Mostafa, Waleed Elgaraihy, Nouran Ashraf, Hala Omar, Rehab Kotb, Is Raafat, Nesma Aboulkhair, Huda Alaa, and Radwa Raafat.

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