EMA5001 Physical Properties of Materials Lecture 0 Introduction. Prof. Zhe Cheng Mechanical & Materials Engineering Florida International University

Transcription

1 EMA5001 Physical Properties of Materials Lecture 0 Introduction Prof. Zhe Cheng Mechanical & Materials Engineering Florida International University

2 2 Course Information & Policy Zhe Cheng ; Office: EC3441 Textbook & Other Course Materials Phase Transformations in Metals and Alloys, D A Porter, K E Easterling, and M Y Sherif, 3 rd edition, CRC Press, (2008). ISBN (0) Policy Attendance required; Turn off cell phone/pagers during class Students can discuss homework problems, but must independently finish it Grade discrepancies resolve in the same day Homework will NOT be collected or graded; solution will be provided Accommodate make-up quiz, tests, or delayed term paper if proven medical necessity Accommodate disability ( and religious holidays NO cheating or plagiarizing in ANY form (Check with me if questions) No excuses will be accepted Will be reported and handled according to FIU policy

3 3 More about Dr. Zhe Cheng Education & Experiences: PhD in Materials Science & Engineering, Georgia Tech, 2008 Research scientist, DuPont, Wilmington DE, Research group website

4 4 Exams & Grading Homework (10%) Term Paper (30%) Mid-term Exam (30%) Final Exam (30%) Grading Scale A: >=90; A-: ; B+: ; B: ; B-: ; C+: ; C: ; D: F: <60

5 5 Term Paper Guidelines Deadlines & Submission ( submission only) Early March: 1 st draft Early April: 2 nd draft Late April: Final submission Term paper plus major references A separate document answering the reviewers question/comments (for 2 nd draft and final version) Format of Main Document Times New Roman, 12 point (Figures/table may use smaller font), single space, 1 inch margin on all sides, print double-sided 4 pages maximum excluding references Grading Missing deadline: zero 4 points for 1 st draft; 4 points for 2 nd draft; 12 points for final term paper 5 points for quality of review provided to other students paper (2 reviews) 5 points for answering/rebutting peer review questions/comments

6 6 Term Paper Content Guidelines on Term Paper Content A detailed critique of at least two or more research papers (must be by different research groups) on a single problem/topic involving kinetics and/or phase transformation in materials in a specific area of interest to you It should have most of the following (but NOT necessary all) Introduction Background Analysis/critiques on Significance and why you are interested Assumptions/Methodology/Mathematical derivation/argument/logic Experimental design, data collection and analysis Consistency and/or contradictions between different studies Unanswered questions Your own analysis/proposed research method or data analysis Recommendations for future work Conclusions References

7 Course Objective & Outcome Objectives Introduce graduate-level principles about kinetics and phase transformation of engineering materials involving phenomena including diffusion, movement of interfaces, solidification, nucleation and growth, phase transformation and kinetics Provide graduate-level training in critical thinking, mathematical analysis, and written communication skills focusing on problems of interests involving kinetics and phase transformation of engineering materials Related MME Program Outcomes a) Ability to apply knowledge of mathematics, science, and engineering e) Ability to identify, formulate, and solve engineering problems g) Ability to communicate effectively i) Recognition of the need for, and a ability to engage in life-long learning k) Ability to use the techniques, skills and modern engineering science necessary for engineering EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 7

8 Thermodynamics (Write down concepts remembered, 3 min) EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 8 Basic Concepts from past

9 9 Thermodynamics Basic Concepts from past 1 st law & 2 nd law Enthalpy, Entropy, Free energy, Basic relationships of thermodynamic functions Temperature & pressure effects Equilibrium Defects in solids Solutions Partial molar quantities Chemical potential Activity and activity coefficient Mixing, Ideal solution & Regular solution Phase diagrams and phase rule Gas solid reactions & Ellingham diagrams Surface & interfaces Electrochemistry

10 10 Kinetics & Phase Transformation Thermodynamics Equilibrium states Possibility & the direction of transformation between states Questions: Initial state Final state Do things ALWAYS reach thermodynamically most favorable states? (2 min) Kinetics & Phase Transformation Rate and dependence of rate on different factors Condition (temp, time, atmosphere, etc.) Composition G How - changes in G 0 G = G - G Composition 0 G G = G - G 0 Metastable state Crystal structure G Final state Morphology/microstructure Depend highly on specific systems Be careful with any generalization G G 0 G G = G - G 0

11 Example/Practical Problem for Kinetics (1) Steel containing 0.4 wt.% of C Modified from slide for Materials Science & Engineering: An Introduction by McCalister 8ed published by Wiley EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 11

12 Hardness (BHN) EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 12 Example/Practical Problem for Kinetics (1) Steel containing 0.4 wt.% of C Processing controls microstructure which determines hardness to a large extent Kinetics and phase transformation in processing influence microstructure and resulting materials properties Martensite (d) Spheroidite (a) 30 mm Pearlite (b) 30 mm Tempered Martensite (c) 4 mm Cooling Rate (ºC/s) 30 mm Data obtained from Figs (a) and with 4 wt% C composition, and from Fig and associated discussion, Callister & Rethwisch 8e. Micrographs adapted from (a) Fig ; (b) Fig. 9.30;(c) Fig ; and (d) Fig , Callister & Rethwisch 8e. Modified from slide for Materials Science & Engineering: An Introduction by McCalister 8ed published by Wiley

13 13 Example/Practical Problem for Kinetics (2) B 4 C synthesis Underlying reaction 2B 2 O 3 + 7C = B 4 C + 6CO How to best control microstructure/micromophology for the reaction/phase transformation process? 1450 o C/3 hour, normal tube furnace Pure B 4 C with structural non-uniformity 1750 o C/3 min, microtube reactor Pure B 4 C, with narrow size distribution P. Foroughi & Z. Cheng, Advances in Ceramic Armor, 2015, p P. Foroughi & Z. Cheng, unpublished results

14 Example/Practical Problem for Kinetics (2) B 4 C synthesis, continued Questions: When will reaction not proceed? Reaction temperature goes higher, what happens? Calculated standard free energy change for 2B 2 O 3 + 7C = B 4 C + 6CO 1150 C/24 hour, normal tube furnace Trace B 4 C with mostly unreacted materials 1900 C/1 sec, graphite tube furnace Pure B 4 C with uniform nano-size powder P. Foroughi & Z. Cheng, Advances in Ceramic Armor, 2015, p Weimer J Am Ceram Soc, 1992, EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 14

15 15 Topics & Planned Schedule Introduction (week 1) Diffusion phenomena and theory (week ~2-5) Interfacial phenomena (week ~6-8) Solidification and nucleation (week ~9, 11) Phase transformation (week ~12-14) Kinetic models in phase transformation (week ~16)

16 Write Down Practical Examples Showing The followings EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 16 Diffusion Interfaces Solidification Diffusional transformation Diffusionless transformation

17 Many Examples for Kinetics & Phase Transformation EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 0 Course Information 17 Diffusion Emitter formation for Si chip & solar cells Li ion releasing from/insertion into cathodes of lithium ion battery Oxygen vacancy diffusion for solid oxide fuel cells H transport through Pd membrane for hydrogen separation Interfaces Grain boundaries in silicon solar cell versus CIGS solar cell Solidification Casting of Si ingot Diffusional transformation Nucleation and growth Spinodal decomposition Diffusionless transformation Martensite transformation in iron and steel for hardening Major Types of Materials in Many Applications!