For many years it has been recognized that engineering materials that are-tough and ductile can be rendered susceptible to premature fracture through their reaction with the environment. Over 100 years ago, Reynolds associated hydrogen with detrimental effects on the ductility of iron. The "season cracking" of brass has been a known problem for dec ades, but the mechanisms for this stress-corrosion process are only today being elucidated. In more recent times, the mechanical properties of most engineering materials have been shown to be adversely affected by hydrogen embrittlement or stress-corrosion cracking. Early studies of environmental effects on crack growth attempted to identify a unified theory to explain the crack growth behavior of groups of materials in a variety of environments. It is currently understood that there are numerous stress-corrosion processes some of which may be common to several materials, but that the crack growth behavior of a given material is dependent on microstructure, microchemistry, mechanics, surface chemistry, and solution chemistry. Although the mechanism by which various chemical species in the environment may cause cracks to propagate in some materials but not in others is very complex, the net result of all environmentally induced fracture is the reduction in the force and energy associated with the tensile or shear separation of atoms at the crack tip.

Proceedings of the NATO Advanced Research Workshop, Reichenhall, Germany, June 23-July, 1986

Inhalt
Introductory Lectures.- Chemistry and Physics of Fracture: An Overview.- What, If Anything, Can Chemistry Offer to Fracture Mechanics?.- Mechanics of Brittle Cracking of Crystal Lattices and Interfaces.- Materials Science of Fracture Processes.- Theory of Fracture.- Plastic Processes at Crack Tips.- Discussion: Remark Concerning the Evidence of Cleavage in Our Experiments in Single Crystals of Fe2.6%Si.- Plastic Flow Instabilities at Crack Tips.- Distributed Damage Processes in Fracture.- A Comparison of Void Growth and Ductile Failure in Plane and Axisymmetric States of Strain.- Solid State Chemistry and Physics of Fracture.- Theoretical Approaches to Materials Design: Intergranular Embrittlement.- Interatomic Forces and the Simulation of Cracks.- Application of the Embedded Atom Method to Hydrogen Embrittlement.- Theory of Environmental Effects on Transgranular Fracture.- Solution Chemistry.- Surface Chemistry in Aqueous Solutions.- Crack-Tip Electrochemistry: Recent Developments.- Electrochemical Thermodynamics and Kinetics and Their Application to the Study of Stress-Corrosion Cracking.- Structure and Properties of Interfaces.- Universal Properties of Bonding at Metal Interfaces.- Structure of Grain Boundaries and Interfaces.- Segregation at Interfaces.- Workshop Sessions.- Workshop Session 1: Novel Aspects of Fracture.- Novel Techniques as Applied to Fracture Process Zone Theory.- Short Presentations.- In Situ TEM Studies of Crack Tip Deformation in Molybdenum.- Quantitative Study of Striations in Stage II Fatigue Crack Growth.- The Brittle-Ductile Transition of Silicon.- Workshop Summary.- Workshop Session 2: Intergranular Embrittlement.- Intergranular Fracture.- Short Presentations.- Structure-Dependent Intergranular Fracture and the Control of Embrittlement of Polycrystals.- Brittle-Ductile Behavior of Materials. [Presentation only].- Workshop Summary.- Workshop Session 3: Hydrogen Embrittlement.- The Role of Hydrogen Transport in Hydrogen Embrittlement.- Hydrogen Induced Fracture.- Short Presentations.- Simple Practical and Theoretical Prediction of Hydrogen Sensitivity of Material. [Presentation only].- Surface Hydrogen and Fracture Stress of 4340 Steel.- Hydrogen Effects in Nickel Based Superalloy Single Crystals.- Hydrogen-Induced Phase Transformations in Thin Specimens of an Austenitic Stainless Steel.- A System of Cracks in Bonded Half Planes.- Stress-Corrosion Cracking of Mild Steel in Anhydrous Ammonia Environments: Nitrogen Embrittlement?. [Presentation only].- Inelastic Neutron Scattering and Resistivity of Hydrogen in Cold-Worked Palladium.- Fracture Initiation Due to Hydrides in Zircaloy-2.- Workshop Summary.- Workshop Session 4: Stress Corrosion and Corrosion Fatigue.- Film-Induced Cleavage During Stress-Corrosion Cracking of Ductile Metals and Alloys.- Corrosion Fatigue of Metals: A Survey of Recent Advances and Issues.- Short Presentations.- Stress Corrosion Cracking of A 508 Steel in Saturated MnS-Solution.- Experiments on Bicrystals Concerning the Influence of Segregation and Slip on Stress Corrosion Cracking.- Stress-Corrosion Cracking of Cu-25Au Single Crystals in Aqueous Chloride Media.- Role of Sulfur in the Formation and the Breakdown of Passive Films.- Breakdown and Formation Process of Titanium Oxide Film During Straining in Aqueous Electrolyte.- Nucleation of Kinks on Cracks. [Presentation only].- Initiation and Evolution of Microcracks During Corrosion Fatigue of BCC Stainless Steels.- Workshop Summary.- Summary Session.- Chemistry and Physics of Fracture: A Conference Summary.- List of Participants.