in this article, the effects of adding zn and conducting age hardening treatment on impression creep properties of mg-5%sn alloy have been investigated. the creep tests were carried out using impression creep method in which a cylindrical punch was used to apply the stress in range of 450 mpa < σimp < 270 mpa and at the test temperatures of 150, 175 and 200 °c. the results showed that age harde...

Indentation creep behaviour of iron aluminide intermetallic (Fe–28Al–3Cr) was studied in the temperature range of 843–963 K. The hardness and the plasticity parameter were also calculated from room temperature to 1273 K. The variation of hardness with time showed that the stress exponent ðnÞ was weakly dependent on temperature. Thermal activation parameter-activation area and energy were also c...

[1] Seismological observations have revealed patches of seismic anisotropy in regions related to mantle upwelling and paleosubduction within an otherwise isotropic lower mantle. A combination of numerical modeling and mineral physics is used to constrain the source of anisotropy in these regions in an effort to better understand lower mantle dynamics and mineral physics. Specifically, it is inv...

Self-organized criticality (SOC) is widely observed in systems ranging from creep deformation of single crystal ice to the movement of glacier. -The behavior of these SOC systems follows a power law distribution, which is timeand space-scale invariant. Previous phase field simulation of single crystal nickel has shown that plastic flow is characterized by intermittent dislocation avalanches, wh...

A continuum theory for high temperature creep of polycrystalline solids is developed. It includes the relevant deformation mechanisms for diffusional and dislocation creep: elasticity with eigenstrains resulting from vacancy diffusion, dislocation climb and glide, and the lattice growth/loss at the boundaries enabled by diffusion. All the deformation mechanisms are described with respect to the...

A model for creep threshold stresses in alloys strengthened by coherent, misfitting precipitates is developed for the case where the precipitate is not sheared, and where there are elastic interactions between a dislocation and the precipitate over which it climbs. Calculations of the particle stress field due to a positive stiffness and lattice parameter mismatch between precipitate and matrix...

A theoretical model is suggested which describes the yield stress dependence on grain size in fine-grained materials, based upon competition between conventional dislocation slip, grain boundary diffusional creep (Coble creep) and triple junction diffusional creep. In the framework of the model, the contribution of diffusional creep mechanisms to plastic deformation increases with reduction of ...

Orientation and temperature dependence of yield stress or CRSS (Critical Resolved Shear Stress) and tension/compression anisotropy of the yield stress or CRSS have been shown by Shah and Duhl (1), Heredia and Pope (2), and Miner et al. (3). Tension/compression asymmetry in the yield strength of Ni-based superalloys has been explained in terms of the “core width effect” (4). Shah and Duhl (5) ob...