Physico-Chemical nanomaterials science

Modeling of deformation fields evolution and defect formation in binary Zr-Nb alloy subjected to irradiation and mechanical loading
Shchokotova O.M., Kharchenko D.O.
Institute of Applied Physics of the NAS of Ukraine,
58, Petropavlivska Str., Sumy 40000, Ukraine. 
E-mail: shchokotova.o@gmail.com

It is known that hardening and embrittlement of construction materials is a result of a microstructure evolution and defects rearrangement produced by external influence like irradiation. That is, microstructure changes determine the system characteristics at the macrolevel. Thus, a study of the formation and dynamics of defects in construction materials is necessary to predict the mechanical and physical properties changing. 
In our work we study a change in mechanical properties of binary Zr-Nb alloy under irradiation. By using the phase field approach with taking into account elastic contribution in the framework of the nonlinear elasticity [1,2] we perform numerical modeling of the deformation fields dynamics and dislocation behavior in irradiated Zr-Nb alloy under mechanical loading. First of all, the previously prepared sample of Zr-Nb alloy was irradiated virtually under various reactor conditions. Then unirradiated and irradiated samples were subjected to deformation.
Distributions of strain, stress and displacements are obtained. It was shown that the slip lines, which are formed by a pair of edge dislocations with opposite Burgers vectors, emerge at the places of accumulation of internal stresses and strains. Irradiation influence on strain-stress curves are analyzed. Irradiation induced changes in a yield strength and ultimate strength are discussed. Obtained results allow to study the endurance of irradiated alloy to mechanical load, and to predict the productivity and reliability of considering alloy.

1.	Minami A., Onuki A. Dislocation formation in two-phase alloys // Phys. Rev. B.-2004.-70.-P. 184114(10).
2.	Onuki A., Furukawa A., Minami A. Sheared solid materials // Pramana – journal of physics.-2005.-64, N 5.-P. 661-677.