Overview No. 3 Fracture-mechanism maps and their construction for f.c.c. metals and alloys

Characterization of Creep Damage in Metals Using Small Angle Neutron Scattering

“…Then the assumption that the chemical potential is determined at all times by the applied stress must be dropped in favor of a stress that increases as the internal, loadbearing area decreases. Harris et al [13] make this adjustment as well as that suggested by Speight and Harris [11] earlier, and find that the Hull and Rimmer model predicts 2 2 In deriving the equation which ultimately leads to their form of eq (7). Speight and Harris [11] assumed that the stress midway between cavities is given by the remote stress, or by an adjusted ligament stress [13].…”

“…Thus, their final result was (6) where p(=f3 2 /f) is the number of cavity nuclei per unit area of grain boundary and f3 is a geometric factor related to the coordination number of nearestneighbor cavities (for example, f3 = 1 for a square array and f3=(4/3)1/4 for an hexagonal array). Although the time-to-fracture and its stress dependence are the important parameters from an engineering perspective, the intermediate result of cavity size as a function of time, and also of cavity size distributions, are the important quantities when making a nondestructive assessment of creep damage for remaining lifetime.…”

“…This phenomenon occurs even in normally ductile materials like copper and nickel [2]. When metals which have fractured under the above conditions are examined microscopically, it is found that they have cavities and cracks distributed throughout the specimen along grain boundaries as shown in figure 1.…”

Optimization of Rolling Conditions in Mg–Al–Ca Alloy Containing Insoluble Second Phase Particles

“…However, the difference reduces at elevated temperatures. 25) The schematic illustration of the variation of workability with temperature for AM60 is shown in Fig. 7.…”

Creep Fracture Mechanisms and Maps in Aisi Type 316 Austenitic Stainless Steels from Distinct Origins

“…They can be visualized in stress versus temperature maps. Ashby et al 7 proposed an experimental map, while Miller and Langdon 8 proposed a model-based map for fracture. Both maps 7,8 are limited in the validity to interpret creep fracture because of simplified hypothesis in their construction.…”