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Mechanical Properties of Metals

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Learn about mechanical properties of metals from this book: Strain, Conventional & True Stresses. Elastic Stress–Strain Relations, Yield Strength, Ductility & Fracture Strength and much more.

Mechanical Properties and Working of Metals and Alloys

By Amit Bhaduri (2018)

SELECTED  CONTENTS

Part I – Mechanical Properties of Metals and Alloys

1 Tension

  • Introduction
  • Strain
  • Conventional and True Stresses
  • Elastic Stress–Strain Relations
  • Elements of Plastic Deformation
  • Types of Tensile Stress–Strain Curve
  • Linear Elastic Properties
  • Nonlinear Elastic Properties
  • Inelastic Properties
    • Yield Strength
    • Ultimate and True Tensile Strength
    • Ductility
    • Fracture Strength and True Fracture Strength
    • Toughness
  • Influence of Temperature on Tensile Properties
  • Strain Rate
  • Testing Machine
  • Notch Tensile Test
  • Tensile Fracture
  • Solved Problems

2 Compression

  • Introduction
  • Standard Specimen
  • Elastic Range
  • Plastic Range
    • Stress and Strain
    • Strain Rate
    • Brittle Materials
    • Ductile Materials
  • Bauschinger Effect
  • Advantages of Compression Over Tension Test
  • Problems in Compression Test
  • Compressive Failure of Materials
  • Solved Problems

3 Hardness

  • Introduction
  • Classification of Hardness
  • Precautions to Avoid Erratic Hardness Measurement
  • Mohs’ Scale of Hardness
  • File Hardness Test
  • Brinell Hardness
    • Principle of Testing
    • Derivation for BHN
    • Indenters, Loads and Loading Periods
    • Method of Testing
    • Anomalous Behaviour
    • Advantages and Disadvantages
  • Meyer Hardness
  • Rockwell Hardness
    • Principle of Testing
    • Loads
    • Indenters
    • Direct-Reading Hardness Dial
    • Hardness Scale
    • Method of Testing
    • Advantages
  • Rockwell Superficial Hardness
    • Principle of Operation
    • Superficial Hardness Scale
    • Merits and Demerits
  • Vickers Hardness
    • Indenters and Loads.
    • Principle of Operation
    • VHN Versus BHN
    • Operational Method
    • Minimum Thickness of Test Section
    • Anomalous Behaviour
    • Advantages and Disadvantages
  • Microhardness (Knoop Hardness)
  • Monotron Hardness
  • Shore Scleroscope Hardness
  • Poldi Impact Hardness
  • The Herbert Pendulum Hardness
  • Nanohardness
  • Relationship to Flow Curve and Prediction of Tensile Properties
  • Solved Problems

4 Bending

  • Introduction
  • Pure Bending
  • Beam Design in Pure Bending
  • Linear Elastic Behaviour
  • Yielding
  • Nonlinear Stress–Strain Relations
  • Shear Stresses in Elastically Bent Beam
  • Solved Problems

5 Torsion—Pure Shear

  • Introduction
  • State of Stress and Strain
  • Relation Between Shear Strain and Angle of Twist
  • Torsional Stresses in Elastic Range
  • Torsional Stresses for Plastic Strains
  • Behaviour of Material in Torsion
  • Elastic Properties
  • Inelastic Properties
  • Torsion Test Versus Tension Test
  • Failure Under Torsion
  • Solved Problem

6 Impact Loading

  • Dynamic Loading and Brittle Fracture
  • Notched-Bar Impact Tests
  • Calculation of Energy Relations
  • Impact Properties
  • Metallurgical Factors Affecting Impact Properties
  • Instrumented Charpy Impact Test
  • Additional Large-Scale Fracture Test Methods
  • Fracture Analysis Diagram (FAD)
  • Solved Problems

7 Creep and Stress Rupture

  • Long-Time Loading at High Temperature
  • The Creep Curve
  • Strain–Time Relations
  • Creep Rate–Stress–Temperature Relations
  • Steady-State Creep
  • Creep Deformation Mechanisms
  • Deformation Mechanism Map
  • The Stress-Rupture Test
  • Concept of ECT and Elevated-Temperature Fracture
  • Presentation of Engineering Creep Data
  • Parameter Methods to Predict Long-Time Properties
  • Stress Relaxation
  • Materials for High-Temperature Use
  • Creep Under Multiaxial Stresses
  • Indentation Creep
  • Solved Problems

8 Fatigue

  • Fatigue Failure
  • Stress Cycles
  • Standard Fatigue Test
  • The S–N Diagram and Fatigue Properties
    • Reason for Existence of Fatigue Limit
  • Statistical Nature of Fatigue
  • Fatigue Crack Nucleation and Growth
    • Fatigue Crack Growth Rate
  • Effect of Mean Stress
  • Stress Fluctuation and Cumulative Fatigue Damage
    • Overstressing, Understressing and Coaxing
    • Cumulative Fatigue Damage
  • Stress Concentration Effect
  • Size Effect
  • Surface Effects and Surface Treatments
    • Surface Roughness and Treatment
    • Surface Properties and Treatment
    • Surface Residual Stress and Treatment
    • Metallurgical Processes Detrimental to Fatigue
  • Effect of Metallurgical Variables
  • Frequency of Stress Cycling
  • Temperature Effect
    • Low Temperature
    • High Temperature
    • Thermal Fatigue
  • Chemical Effects
  • Cyclic Strain-Controlled Fatigue
    • Low-Cycle Fatigue
    • Strain–Life Equation and Curve
  • Creep–Fatigue Interaction
  • Increasing Amplitude Tests
    • Step Test
    • Prot Test
  • Solved Problems

9 Fracture

  • Introduction
  • Theoretical Cohesive Strength
  • Inglis Analysis of Stress Concentration Factor
  • Effects of Notch
  • Characteristic Features of Fracture Process
    • Energy to Fracture
    • Macroscopic Mode of Fracture
    • Microscopic Mode of Fracture or Fractography
  • Griffith Theory of Brittle Fracture
    • Applicability of Griffith Theory
    • Modification of Griffith Theory
  • Elastic Strain Energy Release Rate
  • Stress Intensity Factor
    • Different Crack Surface Displacements
    • Relationship Between Energy Release Rate and Stress Intensity Factor
    • Fracture Toughness
  • Plastic Zone at Crack Tip
    • Effective Stress Intensity Factor
  • Fracture Toughness: Plane Stress Versus Plane Strain
  • Plane-Strain Fracture Toughness (KIc) Testing
    • Specimen Size, Configurations, and Preparation
    • Test, Interpretation of Result and Calculation of (KIc)
    • Kc from KIc
  • Design Philosophy with Fracture Toughness
  • Solved Problems

Part II – Mechanical Working of Metals and Alloys

10 Fundamentals of Mechanical Working

  • Classification of Mechanical Forming Processes
    • Aims of Mechanical Working
    • Different Forming Processes
  • Temperature and Strain Rate
    • Cold-Work-Anneal Cycle
    • Temperature Limits for Hot Working
    • Hot Working Versus Cold Working
    • Warm Working
    • Temperature Change During Working
    • Strain-Rate Effects
    • Choice of Allowable Hot Working Temperature Range
  • Friction
    • Coulomb’s Law of Sliding Friction
    • Shear Friction Factor
    • Measurement of Friction
    • Adverse Effects of Friction
    • Beneficial Effects of Friction
  • Lubrication
    • Material Transfer
    • Functions and Characteristics of a Lubricant
    • Lubrication Mechanism
  • Mechanics of Working Process
    • Slab Method
    • Uniform-Deformation Energy Method
    • Slip-Line Field Theory
    • Upper-Bound Technique
    • Finite Element Method
  • Deformation-Zone Geometry
  • Anisotropy of Mechanical Properties
  • Solved Problems

11 Forging

  • Classification of Forging Processes
  • Types of Forging Operations
  • Forging Equipments
    • Drop Forging Hammer
    • Forging Press
  • Open-Die Forging
  • Closed-Die or Impression-Die Forging
  • Material Loss During Forging
  • Plane Strain Forging of Flat Rectangular Plate
  • Plane Strain Forging of Strip with Inclined Dies
  • Forging of Flat Circular Disk
  • Forging of Circular Disk by Conical Pointed Dies
  • Forging Defects
  • Solved Problems

12 Rolling

  • Fundamentals of Rolling
    • Terminology of Rolled Product
    • Different Methods of Rolling
    • Quantities Characterizing Deformation
  • Classification of Rolling Mills
    • Cluster Mill
    • Sendzimir Cold-Rolling Mill
    • Sendzimir Planetary Hot-Rolling Mill
    • Pendulum Mill
    • Contact-Bend-Stretch Mill
    • Universal Mill
  • Rolling Practice
    • Hot Rolling
    • Cold Rolling
  • Deformation Zone in Rolling
    • Angle of Bite
    • Neutral Point
  • Ekelund Expression for No-Slip Angle
  • Forward Slip
    • Relation with No-Slip Angle
    • Measurement of Forward Slip
    • Importance of Forward Slip
  • Elastic Deformation of Rolls
  • Simplified Assessment of Rolling Load
  • Theory of Rolling: Derivation of Differential Equation
    of Friction Hill
  • Bland and Ford Theory of Cold Rolling
  • Sims’ Theory of Hot Rolling
  • Lever Arm Ratio, Roll Torque and Mill Power
  • Minimum Thickness in Rolling
  • Factors Controlling Rolling
  • Gauge Control
  • Defects in Rolled Products
  • Roll Pass Design Fundamentals
    • Types and Shapes of Passes
    • Gap and Taper of Sides in Pass
    • Pass Arrangement
    • Pass Sequences Used in Rolling of Billets to Rods
    • Pass Sequences Used in Rolling of Billets to Square Bars
  • Manufacture of Tubes and Pipes
    • Production of Seamless Tube and Pipe by Hot Rolling
  • Solved Problems

13 Extrusion

  • Introduction
    • Comparison with Rolling
  • Two Basic Methods of Extrusion
    • Direct Versus Indirect Extrusion
  • Extrusion Equipments
    • Extrusion Dies
  • Metal Flow During Extrusion
  • Factors Influencing Extrusion
  • Estimation of Extrusion Load
    • Open-Die, Indirect and Hydrostatic Extrusions
    • Direct Extrusion Through Conical Converging Die
    • Direct Extrusion Through Square Die
    • Selection of Proper Equation for Ram Load and Stress
  • Strain Rate in Extrusion
  • Extrusion Defects
  • Impact Extrusion
  • Hydrostatic Extrusion
    • Basic Difference Between Hydrostatic and Conventional Extrusion
    • Conventional Hydrostatic Extrusion
    • Differential Pressure Hydrostatic Extrusion
    • Advantages of Hydrostatic Extrusion
    • Disadvantages of Hydrostatic Extrusion
  • Seamless Tube Production by Extrusion
    • Extrusion of Cable Sheathing
  • Application of Slip-Line Field to Steady-State Motion
    • 50% Plane-Strain Frictionless Extrusion
    • 2/3 Plane-Strain Frictionless Extrusion
  • Upper-Bound Solution for Plane-Strain Frictionless Extrusion
  • Solved Problems

14 Drawing: Flat Strip, Round Bar and Tube

  • Introduction
  • Strip Drawing Through Wedge-Shaped Dies
    • Drawing Stress with Friction
    • Frictionless Ideal Drawing Stress
    • Maximum Reduction of Area in a Single Pass With and Without Friction
    • Drawing Stress for Work-Hardening Strip
  • Drawing Stress of Strip Through Cylindrical Dies
  • Treatments of Work Metal Prior to Drawing
  • Drawing Equipments
    • Conical Converging Die
  • Drawing of Rod and Wire
    • Drawing Load and Power with Friction and Back Tension
    • Frictionless Ideal Drawing Stress
    • Maximum Reduction of Area in a Single Pass
    • Redundant Deformation
    • Drawing Stress Versus Die-cone Angle: Optimum Cone Angle, Dead Zone and Shaving
  • Tube Drawing
    • Close-Pass Plug Drawing Stress and Load
    • Close-Pass Mandrel Drawing Stress
    • Maximum Reduction of Area in a Single Pass
    • Tube Sinking
    • Equilibrium Condition of Forces Acting on a Floating Plug
  • Application of Slip-Line Field to Strip Drawing
  • Upper-Bound Solution for Strip Drawing
  • Solved Problems

15 Deep Drawing

  • Fundamentals of Deep Drawing
    • Stresses and Deformation in a Deep-Drawn Cup
  • Deep-Drawing Load
    • Derivation of Mathematical Expression
  • Formability
    • Strain Distribution
    • Maximum Strain Levels: The Forming Limit Diagram
  • Deep Drawability
    • Plastic Strain Ratio
    • Drawing Ratio
  • Effects of Process and Material Variables
    • Effect of Drawing Ratio
    • Radii of Die and Punch
    • Punch-to-Die Clearance
    • Drawing Speed
    • Friction and Lubrication
    • Restraint of Metal Flow
    • Material Parameters
  • Evaluation of Formability
    • Marciniak Biaxial Stretching Test
    • Swift Cup Test
    • Ericksen and Olsen Cup Tests
    • Fukui Conical Cup Test
    • Hole Expansion Test
    • Forming Limit Diagram
  • Deep Drawing Defects
  • Solved Problems

16 High-Energy Rate Forming

  • Introduction
  • Fundamentals of HERF Process
  • Explosive Forming
  • Electromagnetic Forming
  • Electrohydraulic Forming
  • High-Energy Rate Forging
  • Other HERF Methods
  • Solved Problems

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The figures from this book that are useful for understanding aluminium:

the cold-work-anneal cycle illustrating the effects on mechanical properties
Fig. 10.11 – Schematic representation of the cold-work-anneal cycle illustrating the effects on mechanical properties and microstructure (Smith 1969)

Extrusion of solid by (a) direct extrusion and (b) indirect extrusion - mechanical properties
Fig. 13.1 – Extrusion of solid by (a) direct extrusion and (b) indirect extrusion

Schematic view of various extrusion process tooling - mechanical propertiesFig. 13.2 – Schematic view of various extrusion process tooling

Typical curves of extrusion pressure versus ram displacement for direct and indirect extrusion
(a) Typical curves of extrusion pressure versus ram displacement
for direct and indirect extrusion
at a relatively constant billet temperature and
a constant ram speed after initial acceleration;
(b) Division of deformation work for direct extrusion into four zones – I, II, III and IV
Fig. 13.7

Metal flow during extrusion
Fig. 13.8 – Metal flow during extrusion:
(a) Flow along a diagonal path during early stage of extrusion;
(b) Flow normal to force direction at later or final stage of extrusion