Work-hardening phenomena are based on the very fundamental principles (i) that at the position of every dislocation axis the respective resolved shear stress cannot exceed the friction stress, including the self-stress of bowing dislocations, and (ii) that always that structure forms which among those accessible by the dislocations minimizes stored energy per unit length of dislocation line. Such dislocation structures have been named LEDSs. The corresponding work-hardening theory, the mesh length theory, is applicable to all materials deforming via gliding dislocations and to all types of deformation. Results previously achieved with the mesh length theory are summarized, and a number of new developments are discussed. Depending on the dislocation structures formed, the work-hardening behavior differs. Easily intersecting glide causes dislocation cell structures with almost dislocation-free cell interiors delineated by dislocation rotation boundaries. Pronounced planar glide causes Taylor lattices characterized by local planar order parallel to the one or perhaps two most highly stressed glide plane(s), no systematic lattice rotations, and overall uniform dislocation density. The most widely observed basic features of work hardening are explained in general terms. Specific applications are indicated for layer-type crystals, h.c.p. single crystals, single-crystal and polycrystalline pure f.c.c. metals and α-brass-type alloys, precipitation-hardened materials and steels. Included are the different stages of work hardening, dynamical effects in low temperature plasticity, the general characteristics of grain boundary strengthening and the Hall-Petch relationship. In addition, proposed explanations for (i) glide system interactions in polyslip resulting in microbands and affecting texture formation, and (ii) creep without stress dependence of dislocation density, are discussed.

Theory of plastic deformation: - properties of low energy dislocation structures

Environmentally Assisted Cracking: Overview of Evidence for an Adsorption-Induced Localised-Slip Process,

https://research.birmingham.ac.uk/portal/files/45381603/Liu_et_al_Dislocation_network_in_additive_Materials_Today_2017.pdf

Dislocation network in additive manufactured steel breaks strength–ductility trade-off

http://li.mit.edu/Archive/Papers/12/Neeraj12SrinivasanAM.pdf

Hydrogen embrittlement of ferritic steels: Observations on deformation microstructure, nanoscale dimples and failure by nanovoiding

The transgranular stress-corrosion cracking of ductile alloys (and at least one pure metal) leads to a fracture appearance characteristic of cleavage. The experimental and theoretical background of this form of metal failure is reviewed. The discontinuous nature of crack growth in α-brass and copper is demonstrated using a combination of acoustic and electrochemical measurements. Short-range cleavage of ductile metals is shown to be theoretically possible provided the thin surface film which is responsible for crack initiation has the appropriate properties. The important parameters determining the effectiveness of films in initiating cleavage include the film-substrate misfit, the strength of the bonding across the film-substrate interface, the film thickness and the film ductility. Suitable combinations of these parameters which can lead to micro cleavage are determined by the state of coherency of the interface and the fracture toughness of the substrate. For example, if a ductile de-alloyed l...

H.G.F. Wilsdorf

Papers

The ductile fracture of metals: A microstructural viewpoint

Crack initiation at dislocation cell boundaries in the ductile fracture of metals

Low energy dislocation structures associated with cracks in ductile fracture

Observations on the effect of temperature rise at fracture in two titanium alloys

Characterization of the effect of alloying elements on the fracture toughness of high strength, low alloy steels