CLASS1AND 2 - NITC - National Institute of Technology

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ME6501 MECHANICAL BEHAVIOUR OF MATERIALS

• Module I (10 hours)

• Concepts of crystals, Plastic deformation by slip and twinning, Slip systems in FCC, BCC and

HCP lattices, Critical resolved shear stress for slip, Theoretical shear strength of solids,

Stacking faults and deformation bands.

Observation of dislocations, Climb and cross slip, Dislocations in FCC and HCP lattice, Partial dislocations, Stress fields and energies of dislocations, Forces between dislocations,

Interaction of dislocations, Dislocation sources and their multiplications.

• Module II (10 hours)

• Strengthening from grain boundaries, Grain size measurements, Yield point phenomenon, Strain aging, Solid solution strengthening,

Strengthening from fine particles, Fiber strengthening, Cold working and strain hardening, Annealing of cold worked metal.

Fracture in metals, Griffith theory of brittle fracture, Metallographic aspects of fracture,

Fractography, Dislocation theories of brittle fracture, Ductile fracture, Notch effects, Strain energy release rate in fracture, Fracture toughness and design.

• Module III (10 hours)

• Fatigue of metals, The S-N curve, Low cycle fatigue, Fatigue crack propagation, Effect of stress concentration on fatigue, Size effect,

Surface effects and fatigue, Fatigue under combined stresses, Effects of metallurgical variables and fatigue, Corrosion fatigue, Design for fatigue, Effect of temperature on fatigue.

Creep and stress rupture, Creep curve, Stress rupture test, Mechanism of creep deformation,

Activation energy for steady state creep,

Superplasticity, Fracture at elevated temperature, Creep resistant alloys, Creep under combined stresses.

• Module IV (10 hours)

• Tension test, Stress-strain curves, Instability in tension, Ductility measurement, Effect of strain rate, temperature and testing machine on flow properties, Stress relaxation testing, Notch tensile test, Anisotropy of tensile properties.

Hardness test, Brinnel, Rockwell and Vickers hardness, flow of metal under the indenter, relationship between hardness and flow curve, micro hardness testing, Hardness at elevated temperatures.

• Text Book : Dieter M. George, Mechanical

Metallurgy, McGraw- Hill Inc., 2001.

• References:

• 1. Deformation and fracture mechanics, Richard

W Hertzberg John Wiley & Sons

• 2. Mechanical behaviour of Materials, Frank A

McCLINOCK and ALI S ARGON

• 3. Physical Metallurgy Principles, Reed Hill and

Robert E, East West Press

• 4. Structure and properties of Materials, Hyden

W. M. Vol. 3, McGraw Hill

• 5. Plastic deformation of Metals , Honeycombe,

Arnold Press.

• An understanding of mechanical behavior is important to both the development of new materials and the selection of appropriate materials for many applications.

• This is best investigated and understood by integrating solid mechanics with the microstructural basis of deformation and fracture.

• The course is intended as a formal basis for students to pursue an integrated approach to the mechanical behavior of material.

Text:

Mechanical Behaviour of materials- Thomas Courtney

(2 nd Ed.McGraw Hill)

References:

1. Mechanical Behaviour of Materials- Mark Andrew Meyers &

K.K. Chawla (Prentice Hall)

2. Mechanical Metallurgy- George Dieter (McGraw Hill)

3. Materials Science and Engineering-William Callister,Jr. (Wiley)

4. Engineering Materials,1, Michael Ashby and David Jones

(Pergamon)

5. Deformation and Fracture Mechanics of Engineering Materials,

Richard W. Hertzberg, (Wiley &Sons, NY)

Key Phrases - Statistically Improbable

Phrases (SIPs): transient creep model , maximum shear criterion , shear stress yield criterion , engineering fracture strength , making life estimates , nominal stress amplitude , multistage spring , nonzero mean stress , environmental crack growth , notched member , creep elements , standard compact specimen , maximum normal stress criterion , short fatigue lives , principal normal stresses , frictional sliders , uniaxial curve , deformation plasticity theory , current crack length , true fracture strength , plasticity limitations , elastic stress concentration factor , shear stress criterion , elliptical hysteresis , principal normal strains

Inside This Book: First Sentence

Designers of machines, vehicles, and structures must achieve acceptable levels of performance and economy, while at the same time striving to guarantee that the item is both safe and durable

Provides comprehensive treatment of the mechanical behavior of materials within a balanced mechanics-materials approach.

Covering a range of materials, including metals, polymers, ceramics, and composites, this book presents the properties of materials while addressing the principal ideas behind theories of mechanical behavior.

It includes broad treatment of flow and fracture criteria. It presents various mechanisms for tailoring the strength and toughness of materials.

It also provides references and a list of suggested readings in each chapter.

A valuable reference book on the mechanical behavior of materials for all practicing Mechanical and Materials Engineers.

This text differs from others because the treatment of plasticity has greater emphasis on the interrelationship of the flow, effective strain and effective stress and their use in conjunction with yield criteria to solve problems.

• The treatment of defects is new. Schmid’s law is generalized for complex stress states. Its use with strains allows for prediction of R-values for textures.

Another feature is the treatment of lattice rotations and how they lead to deformation textures.

The chapter on fracture mechanics includes coverage of Gurney's approach.

Much of the analysis of particulate composites is new. Few texts include anything on metal forming.

• Includes numerous examples and end-ofchapter problems

Emphasizes quantitative problem solving

• Briefer, less expensive, and more modern than competition

This textbook is for courses on Mechanical Behavior of Materials taught in departments of Mechanical Engineering and Materials Science.

The text includes numerous examples and problems for student practice. The book emphasizes quantitative problem solving. End of the chapter notes are included to increase students' interest .

MATERIALS IN TODAY’S WORLD

• Introduces the field of materials science in a format suitable for non-engineering students. Materials and their properties are examined in the context of their use in everyday objects including sports equipment, automobiles, aircraft, display screens, compact disc players, hip-replacements, etc. The role materials have played and will continue to play in shaping society will be discussed. Examples and demonstrations will be the major component in this course. Course is intended as an elective for non-engineering students. Course may not be taken as a technical elective by students in the

College of Engineering. 3 hours.

How to study?

BEHAVIOUR

Eg: Human Behaviour-

The potential and expressed capacity for physical, mental, and social activity during the phases of human life.

Human beings, like other animal species , have a typical life course that consists of successive phases of growth, each of which is characterized by a distinct set of physical, physiological, and behavioral features.

Class: 2

• Introducing students to the Foundry

Section of Central Workshop

• Primary ideas on moulding- familiarise with the sequence, importance of ramming, gating design, sand properties, pattern materials and pouring

Class:3

For self study:

• Crystals; FCC,BCC,HCP

• About Miller Indicesone family

• Directions as [ ] and < >

• Planes as ( ) and { }

• Atomic Packing Factor

• Defects- Point, Line, Surface, Volume

• Deformations/ Dislocations:

Edge,

Screw

• Slip Phenomenon

About Tension Test: Its Importance-

• Engineering Stress and True stress

Elastic Region, Proportionality Limit,

Yielding, Strain hardening, Necking

• Loading and unloading in elastic limit

• Yield Stress, Ultimate Stress, Fracture

Stress

Examples- transmission tower/ casting

MECHANICAL BEHAVIOUR,

TESTING

AND

MANUFACTURING PROPERTIES

OF MATERIALS

National Institute of Technology Calicut

STRENGTH

• Glass Fibers

• Graphite Fibers

• Kevlar Fibers

• Carbides

• Molybdenum

• Steels

• Tantalum

• Titanium

• Copper

• Reinforced Plastics

• Termoplastics

• Lead

HARDNESS

• Diamond

• Cubic Boron Nitride

• Carbides

• Hardened Steels

• Titanium

• Cast Irons

• Copper

• Thermosets

• Magnesium

• Thermosets

• Thermoplastics

• Lead

• Rubbers

TOUGHNESS

• Ductile materials

• Reinforced Plastics

• Thermoplastics

• Wood

• Thermosets

• Ceramics

• Glass

• Ceramics

• Reinforced Plastics

• Thermoplastics

• Tin

• Thermoplastics

STIFFNESS

• Diamond

• Carbides

• Tungsten

• Steel

• Copper

• Titanium

• Aluminium

• Tantalum

• Plastics

• Wood

• Thermosets

STRENGTH/DENSITY

• Reinforced Plastics

• Titanium

• Steel

• Aluminium

• Magnesium

• Beryllium

• Copper

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