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
- Diatomic Traps
- Thermodynamics of Dissolution
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
- Sieverts’ Method
- 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
- Pure Aluminium
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
- Diffusion in a Uniform Isotropic Medium
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
- Practical Considerations
- 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
- Nucleation of Micropores
- 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
- Wrought Products
- 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
- CONTROL OF 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
- The State of Occluded Hydrogen in the Solid Metal
- 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