The stored energy of cold work

Calorimetry of deformed aluminum reinforced with alumina particles

“…Recrystallization of the present composites is therefore expected to be faster compared to identically deformed unreinforced 99.98% pure aluminum. It is known that deformed high purity aluminum exhibits several thermal peaks upon annealing (7,(14)(15)(16)(17). All but the highest-temperature peak frequently occur below room temperature and correspond to the annihilation of point defects by recovery.…”

“…Many expressions have been proposed to link dislocation density with stored energy in deformed metals (7). In metal matrix composites, internal stresses, which are often present within the unloaded composite after plastic deformation due to unequal load partition between matrix and reinforcement and to inhomogeneity in plastic deformation of the matrix (18), may also contribute to the stored energy of cold work.…”

“…If we assume that residual stresses in the composite are negligible, we can use Kuhlmann-Wilsdorf s equation for the volumetric energy of dislocations in cell walls (7,19,20 A lower bound for the dislocation density in the matrix, Pmin, can be estimated if we assume that the average residual stress in the matrix after unloading of the composite, <c~a>, is equal to its flow stress oy, estimated from:…”

Fatigue hysteresis and acoustic emission. Parts 1 and 2

“…Ad ( This value is consiste;it with calorimetric estimates obtained from studies of the stored energy of cold work (Bever et al, 1973). Equation (2.10) explains in a simple way how the total energy dissipated in high cycle hysteresis -UT in (2.6) -can become very large, and at the same time, the total energy dissipated in damage -Ud in (2.8) -can remain fixed.…”

Post-yield compressed semicrystalline poly(butylene terephthalate): energy storage and release

“…In fact, more recent studies conducted on several glassy and semicrystalline polymers and blends [4 -7] showed that 45-85% of the mechanical work of deformation can be converted into internal energy and stored in the material after unloading. In contrast, 90-98% of the mechanical work is generally dissipated in stretching various common metals [8].…”