Effects of hydrogen in aluminium and its alloys / D.J. Talbot

 

 

 

 

 

 

 

 

BRIEF CONTENTS

1 OVERVIEW OF THE EFFECTS OF OCCLUDED HYDROGEN

  • STATES OF OCCLUSION
    • Nature of Hydrogen
    • Solutions
    • Hydrogen Traps
  • QUANTITATIVE APPROACHES
    • Hydrogen Contents
    • Solubilities
    • Diffusivity
  • ENVIRONMENTAL SOURCES OF HYDROGEN
    • Humidity
    • Rolled Surfaces
  • CONTROL OF ARTIFACTS ASSOCIATED WITH HYDROGEN
    • Interdendritic Porosity
    • Secondary Porosity
    • Extraneous Sites for Defects
    • Inherited Characteristics
  • REFERENCES

2 ALUMINIUM AND ITS ALLOYS

  • STRUCTURE AND PROPERTIES OF ALUMINIUM
    • Physical States
    • Crystal Structure
    • Chemical Properties
  • SUMMARY OF COMMERCIAL ALLOYS AND APPLICATIONS
    • Alloy Systems
    • Alloys Used without Heat-Treatment
      • Commercial Pure Aluminium Grades (AA 1100 Alloy Series)
      • The Aluminium-Manganese Alloy AA 3003
      • Aluminium-Magnesium Alloys (AA 5000 Series)
      • The Aluminium-Magnesium-Manganese Alloy AA 3004
    • Heat Treatable (Ageing) Alloys
      • Aluminium-Copper-Magnesium Alloys (e.g. AA 2024)
      • Aluminium-Zinc-Magnesium Alloys (e.g. AA 7075)
      • Aluminium-Magnesium-Silicon Alloys (e.g. AA 6061)
      • Aluminium Alloys Containing Lithium
    • Casting Alloys
  • REFERENCES

3 SUMMARY OF MANUFACTURING ROUTES AND PROCEDURES

  • EXTRACTIVE METALLURGY OF ALUMINIUM
    • Extraction of Alumina from Bauxite by the Bayer Process
    • Extraction of Aluminium by the Hall-Herault Process
      • The Reduction Cell
      • Metal Purity
    • INGOT CASTING
      • Melting and Preparation of the Liquid Metal
      • Delivery of Liquid Metal from Furnace to Moulds
      • The Direct Chill CDC) Semicontinuous Process
        • Regular DC Casting
        • Low Head Casting
        • Level Transfer Casting
      • ROLLING FLAT PRODUCTS
        • Hot Rolling
        • Cold Rolling
        • Foil Rolling
      • FABRICATIONOF RODS TUBES AND SECTIONS
        • Extrusion
        • Rod and Section Rolling
        • Tube and Wire Drawing
      • FOUNDRY PRODUCTS
      • FORGING
      • RECYCLING
      • REFERENCES

4 HYDROGEN OCCLUSION IN ALUMINIUM AND ITS ALLOYS

  • DILUTE SOLUTIONS OF HYDROGEN IN ALUMINIUM
    • Thermodynamics of Dissolution
      • Selection of Standard States
      • Pressure-Dependence of Solubility and Sievert’s Isotherm
      • Temperature-Dependence of Solubility and the Van’t Hoff Isobar
    • Some Fundamental Aspects of Hydrogen Solutions
      • Electronic Approach to the Enthalpy of Solution
      • Statistical Approach to Solubility
      • Crystallographic Aspects of Hydrogen Solutions
    • SPONTANEOUS BREAKDOWN OF SUPERSATURATED SOLUTIONS
      • Nucleation and Growth of Hydrogen-Filled Micropores
      • Pore Stability Diagram
    • HYDROGEN TRAP SITES
      • Diatomic Traps
        • Microporosity
        • Extraneous Artifacts
      • Monatomic Traps
      • Chemical Traps
        • The Stability of Lithium Hydride in Aluminium-Lithium Alloys
        • The Stability of Sodium Hydride in Aluminium and its Alloys
      • QUANTITATIVE DESCRIPTION OF OCCLUDED HYDROGEN IN INDUSTRY
        • Determinate and Indeterminate Occluded Systems
        • Hydrogen Content
      • REFERENCES

5 THE DETERMINATION OF HYDROGEN IN ALUMINIUM AND ITS ALLOYS

  • GENERAL PRINCIPLES
    • Collection Methods
    • Methods Based on Measurements of Hydrogen Activity
  • THE VACUUM EXTRACTION TECHNIQUE
    • Operating Principles
    • Equipment
      • Gas Collection and Analysis System
      • Arrangements for Heating Samples
    • Procedures
      • Sample Preparation
      • Conditioning the Sample Tube
      • Extraction of Hydrogen
      • Correction for Residual Gases
      • Correction for Extraneous Hydrogen
      • Care and Maintenance of Sample Tubes
    • On-Line Data Processing by Computer
    • Validity of Results
      • Reproducibility of the Method
      • Absolute Accuracy
    • THE TELEGAS
      • Validation of Principle
      • Micro Carrier Gas System
      • Practical Operation and Characteristics
        • Operation
        • Accuracy
        • Example of Telegas Application in Industrial Experiments
        • Further Developments
      • RAPID CARRIER GAS METHOD
      • APPLICATIONOF REDUCED PRESSURE TO LIQUID METAL SAMPLES
      • ASSESSMENTOF APPLICATIONS
      • REFERENCES

6 SOLUBILITIES OF HYDROGEN IN ALUMINIUM AND ITS ALLOYS

  • TECHNIQUES FOR MEASURINGSOLUBILITIES
    • Sieverts’ Method
      • Equipment
      • Procedures
      • Validity of Sieverts’ Method
    • Absorption- Desorption Methods
      • Equipment
      • Procedures
    • Procedures for Alloys with Active Volatile Components
    • Reliability of Determinations
  • PRESENTATION OF VALUES FOR SOLUBILITY
    • Conventional Descriptions of Solutions
    • Practical System Based on Hydrogen Content
    • Relation of Hydrogen Content to Molality and Mole Fraction
  • CRITICAL ASSESSMENTS OF PUBLISHED VALUES FOR SOLUBILITIES
    • Pure Aluminium
      • Pure Liquid Aluminium
      • Pure Solid Aluminium
      • Comparison of Solubilities in Liquid and Solid Pure Aluminium
    • Aluminium-Copper and Aluminium-Silicon Alloys
      • Liquid Aluminium Copper Alloys
      • Liquid Aluminium-Silicon Alloys
    • Aluminium-Lithium Alloys
      • Liquid Aluminium-Lithium Alloys
      • Nature of Hydrogen Solutions in Liquid Aluminium Alloys Containing Lithium
      • Solid Aluminium-Lithium Alloys
      • Association of Solute Hydrogen with Lithium-Rich Clusters
      • Nature of Hydrogen Solutions in Solid Aluminium Alloys Containing Lithium
    • REFERENCES

7 THE DIFFUSION OF HYDROGEN IN ALUMINIUM AND ITS ALLOYS

  • 1 MATHEMATICS OF DIFFUSION
    • Diffusion in a Uniform Isotropic Medium
      • Absorption in or Desorption from an Infinite Plane Sheet
      • Absorption in or Desorption from an Infinite Cylinder
      • Dimensionless Parameters
    • Diffusion in a Field of Traps
      • Linear Isotherm
      • Non-Linear Isotherm
    • DETERMINATION OF DIFFUSIVITY COEFFICIENTS
      • Approach
      • Procedures for the Solid Metal
      • Evaluation of Diffusion Coefficients
    • DIFFUSIVITY IN ALUMINIUM
      • True Diffusivity in Solid Pure Aluminium
      • Diffusivity in Manufactured Products
      • Diffusion with Enhanced Trapping
      • Diffusivity of Hydrogen in Pure Liquid Aluminium
    • DIFFUSIVITY IN SOLID ALUMINIUM LITHIUM ALLOYS
      • Measured Values
      • Mathematical Analysis
    • REFERENCES

8 ABSORPTION OF HYDROGEN IN ALUMINIUM AND ITS ALLOYS

  • INDUSTRIAL HYDROGEN SOURCES
  • THE CAPACITY OF THE METAL TO ACCEPT HYDROGEN
  • HYDROGEN ABSORPTION BY LIQUID METAL
    • Practical Considerations
      • Furnace Atmospheres
      • Charge Materials
    • Reaction Kinetics
      • Oxygen Activity Gradients in Oxidation Products on Aluminium
      • Conditions for Reduction of Water Vapour to Hydrogen
      • Relevant Phases in the Alumina- Water System
      • Phase Equilibria
      • Correlation of Phase Relationships with Hydrogen Absorption
  • ABSORPTION OF HYDROGEN IN SOLID METAL FROM THE ATMOSPHERE
    • Pure Aluminium
    • Aluminium- Magnesium Alloys
      • Theoretical Treatment of Selective Oxidation
      • Hydrogen Absorption in Aluminium Magnesium Alloys from Clean Humid Air
      • Hydrogen Absorption from Air Polluted with Sulphur Dioxide
      • The Influence of Pore Nuclei
      • Inhibition by Potassium Borofluoride
    • Aluminium-lithium Alloys
      • Theoretical Treatment of Selective Oxidation
      • Hydrogen Absorption in Aluminium Lithium Alloys from Clean Humid Air
      • Lithium Hydride as a Sink for Absorbed Hydrogen
      • The Influence of Sulphur Pollution in the Atmosphere
  • HYDROGEN ABSORBED FROM ROLLED SURFACES
    • Characteristics of Hot-Rolled Surfaces
    • Profile of the Surface Hydrogen Source
    • Hydrogen Absorption in Annealing During Manufacture
      • Simulated Annealing of Hot Rolled Aluminium
      • Mathematical Model of Hydrogen Absorption
      • Effect of Cold Rolling
  • REFERENCES

9 POROSITY AND RELATED ARTIFACTS IN MANUFACTURED PRODUCTS

  • EVALUATION OF POROSITY
  • INTERDENDRITIC POROSITY
    • Theory of Formation
    • Distribution in Semicontinuously Cast Ingots
    • Persistence Through Thermal and Mechanical Processing
    • Porosity in Near Net Shape Castings
  • SECONDARY POROSITY
    • Nucleation of Micropores
      • Disproportionation of Hydrogen Solutions
      • Stability of Micropores
    • Secondary Pore Systems in 99.2% Aluminium (AA 1100)
      • Effects of Thermal and Mechanical Treatments
      • Correlation with Hydrogen Content
    • Secondary Pore Systems in Very Pure (99.99%) Aluminium
      • Effect of Homogenising Semicontinuously Cast Ingots
      • Wrought Forms
    • Preferred Pore Sites
  • REFERENCES

10 CONTROL OF HYDROGEN AND ITS EFFECTS IN MANUFACTURED PRODUCTS

  • DEFECTSASSOCIATEDWITHHYDROGEN
    • Wrought Products
      • Sheet and Extrusions
      • Foil
      • Thick Plate and Forgings
    • Near Net Shape Castings
    • Alloys Containing Lithium
  • CONTROL AND REMOVAL OF HYDROGEN FROM THE LIQUID METAL
    • Transport of Hydrogen Across the Liquid Metal Surface
    • Degassing by Purging
      • Theoretical Basis
      • Selection of Purge Gases
      • Degassing In Furnaces
      • In-line Degassing
      • Economical Use of Degassing Procedures
      • Multipurpose Liquid Metal Treatment Systems
      • The Special Case of Alloys Containing Lithium
    • CONTROLOF HYDROGEN AND ITS EFFECTS IN THE SOLID METAL
      • The State of Occluded Hydrogen in the Solid Metal
        • Solution
        • Interdendritic Porosity
        • Secondary Porosity and Unstable Solutions
        • Hydrides
      • Absorption of Hydrogen from Atmospheric Humidity
        • Pure Aluminium
        • Aluminium Alloys Containing Magnesium
        • Aluminium Alloys Containing Lithium
      • Absorption of Hydrogen from Surfaces of Mill Products
      • Redistribution and Expansion of Secondary Porosity
      • Mechanically-Generated Defects
      • Inherited Characteristics
    • REFERENCES

APPENDIX 1. CALIBRATION OF VACUUM EXTRACTION EQUIPMENT

APPENDIX 2. SELECTIVE OXIDATION OF MAGNESIUM AND LITHIUM IN ALLOYS

  • STANDARD GIBBS FREE ENERGIES OF FORMATION
  • FORMATION OF OXIDES ON ALUMINIUM-MAGNESIUM ALLOYS
    – Equilibrium Oxygen Activities
    – Equilibrium Constants
    – Example of Calculations
  • FORMATION OF OXIDES ON ALUMINIUM-LITHIUM ALLOYS
  • HYDRATION OF MAGNESIUM AND LITHIUM OXIDES
  • REFERENCES

SUBJECT INDEX