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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

PREVIEW

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


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


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

Fig. 13.2 – Schematic view of various extrusion process tooling


(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


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