Ionic Bonding - Material Science and Engineering - Exam, Exams of Material Engineering

Download Ionic Bonding - Material Science and Engineering - Exam and more Exams Material Engineering in PDF only on Docsity! - 1 - MECH 6012 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 3 Examinations 2007/08 Module Title: Material Science & Engineering Module Code: MECH6012 School: Mechanical & Process Engineering Programme Title: Bachelor of Engineering (Honours ) in Mechanical Engineering – Stage 1 Programme Code: EMECH_8_Y1 External Examiner(s): Mr. Peter Clarke, Prof. Michael Gilchrist Internal Examiner(s): Dr Gerard Kelly Instructions: Answer Q1 and any two other questions. All questions carry equal marks Note if you attempt question 4 please return the equilibrium diagram with your answer book. Duration: 2 HOURS Sitting: Autumn 2008 Requirements for this examination: Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator. - 2 - MECH 6012 Q1. (a) Briefly describe the difference between ionic, covalent and metallic bonding and how they share electrons. Give an example of each type of bond. (5 marks) (b) Some classes of materials exhibit directionality in their properties. Identify which classes of engineering materials and explain why. (5 marks) (c) Briefly describe the relationship between bond energy and material properties such as Elastic modulus, CTE and Tm. (5 marks) (d) Identify 4 principle metal crystalline structures. (5 marks) (e) Briefly describe the relationship between defects and plasticity in crystalline structures. (4 marks) (f) If E is the modulus of elasticity of a brittle elastic solid, what is its theoretical cohesive strength? (4 marks) (g) Describe the steps necessary to case harden a plain carbon steel whose carbon content is less than 0.3% C. (4 marks) Q2. A tensile test is performed on a metal sample, and it is observed that a true plastic strain of 0.16 is produced when a true stress of 500 MPa is applied; for the same metal the value of K, the strength coefficient is 825 MPa . Firstly compute n and then calculate the true strain that results from a true stress of 600 MPa (33 marks)