Deformation Mechanisms

MATS23502 Deformation Mechanisms 10 Semester 2 Undergraduate Level 5 Leandro Maio Unit coordinator Department of Materials 1 FHEQ level (Framework for Higher Education Qualifications) ' Middle part of Bachelors ' European Credit Transfer & Accumulation System Rating : 5.0 This unit is concerned with the mechanisms of deformation and strengthening in crystalline and non-crystalline solids. This unit is concerned with the mechanisms of deformation and strengthening in crystalline and non-crystalline solids. Lecture topics include.Deformation and strengthening of crystalline solidsCrystallographic slip, the Schmid factor, Burger’s vectors for complete dislocations in metals, polymers ceramics and graphene.Non-conservative motion of dislocation: cross slip and climb, Peirels-Nabarro stress (metals vs ceramics, minerals) derivation of elastic properties of dislocations, stored energy.Dislocation bowing, dislocation reactions and forces between dislocations, dislocation structures, dislocations in real materials: partial dislocations and stacking faults.Dislocation interactions: Taylor hardening, locks, jogs, strain hardening, solution and precipitation hardening, ordering, grain size effects, twinning.Thermally activated deformation: thermal activation of climb and cross-slip, diffusion based flow, introduction to dislocation creep. Deformation and strengthening of non-crystalline solids:Viscoelasticity, glass transition, deformation of metallic and non-metallic glasses. Deformation of polymers, cross-linking, co-polymers.  The unit aims to:Provide an overview of the deformation mechanisms in crystalline and non-crystalline solids.Provide a quantitative treatment of the strengthening mechanisms using simple physical models.Provide a theoretical framework for the time dependent deformation of non-crystalline solids and how it is affected by microstructure. A greater depth of the learning outcomes will be covered in the following sections:<ul><li>Knowledge and understanding</li><li>Intellectual skills</li><li>Practical skills</li><li>Transferable skills and personal qualities</li></ul> Understand the origins of the strength of solids and its link to structure and microstructure.Understand the physical mechanisms of plastic deformation in crystalline solids.Know the concepts of slip, cross-slip, climb, diffusion and twinning.Recognize the different defect types in crystalline solids and understand the role they play in plastic deformation.Understand the concept of stored energy.Understand the mechanisms that give rise to work hardening.Know and understand how crystalline solids are strengthened by solid solution, grain size, and second phase particles.Understand the effect of temperature on deformation mechanisms.Understand the mechanisms responsible for viscoelasticity and how it depends on the molecular structure.Understand the glass transition phenomenon, factors that affect it and how it can be determined.  Show improved logical reasoning, problem solving and ability in applied mathematics.The ability to use simple models to calculate the strength of crystalline solids.  Use bend testing and microscopy to investigate the strengthening mechanism of light alloysCarry out and interpret experiments to determine the glass transition temperature.  Convert word problems into equations and numerical answers.Develop techniques for estimating the results from calculations.Work effectively in a group to solve problems.Compose simple technical reports on laboratory tests.  Lectures, group tutorials (problem sessions), recommended textbooks, web resources, past exam papers, electronic supporting information (Canvas), peer-assisted study sessions (PASS).  1 Written exam 70% 2 Written assignment (inc essay) 30% Written and verbal N Introduction to dislocations” D. Hull and D.J. Bacon, Oxford : Butterworth Heinemann 4th ed, 2001“The plastic deformation of metals” R.W.K. Honeycombe, London : Edward Arnold 2nd ed. 1984“Mechanical metallurgy” George E. Dieter,: McGraw-Hill 2nd ed., New York ; London 1976.  “Dislocations and plastic flow in crystals”, Alan Cottrell, Clarendon Press, Oxford 1953“Introduction to Polymer Science”, R.J. Young and P.A. Lovell, 2nd or 3rd Edition, CRC Press Lectures 22 0 78