A sigmoidal curve in a double-logarithmic scale of stress and strain rate was observed in the creep of Ti/15TiB at 1123 K and was classified into a complete-diffusional-accommodation region corresponding to composite weakening, a diffusional-accommodation-controlled region and a plastic-accommodation-controlled region corresponding to composite strengthening with increasing stress.
Three versions of the notch correction method are successively introduced, a linear one which directly uses Eshelby's solution to compute stresses and strains at the notch, a non-linear method that takes into account plastic accommodation through a β-rule correction and, finally, the extended method that is based on the transformation field analysis methods.
The transformation of a fraction of the austenite into a hard martensite plate is simulated, accounting for a transformation strain, and leading to complex elastic and plastic accommodation.
The plastic accommodation by γ also relieves the constraint imposed on transforming β and decreases the energy barrier for transformation.
As lack of plastic accommodation at grain boundaries often leads to brittle intergranular fracture, incorporation of a ductile intergranular phase is promising for providing strain accommodation for transformation nearby and improving superelastic fatigue life.
It has also been shown that bainite poles can get shifted due to plastic accommodation of austenite caused by martensite laths.
In the high-strain-rate region, power-law creep controlled by plastic accommodation was observed, while linear creep controlled by diffusional accommodation was not observed around the diffusional accommodation rate.
The microstructures of the samples implied that this austenitic phase stability was due to the occurrence of simultaneous twinning during tensile deformation, and the effect of the plastic accommodation induced by the multiple deformations is discussed in this paper.
Moreover, the model is capable of capturing both TRIP effects, the contribution due to load-biased orientation of bainite-variants ("Magee effect") and plastic accommodation of the new phase ("Greenwood Johnson effect").
A good combination of coarse WC particles and WC-Co nanocomposite facilitates high properties of the coating, with the former mainly bearing the load and resisting against penetration of the wear debris, and the latter providing high hardness and also plastic accommodation in the wearing process.
The results are providing new experimental evidence on subjects critically relevant to the understanding of the atomic mechanisms controlling bainitic ferrite formation, such as the incomplete transformation phenomenon, the carbon supersaturation of ferrite, and the plastic accommodation of the surrounding austenite.
