Physico-Chemical nanomaterials science

Modeling plastic deformation and mechanical properties change
of Zr-Sn alloys subjected to irradiation in three dimensions
Shchokotova O.M., Kharchenko D.O., Kharchenko V.O.
Institute of Applied Physics of the NAS of Ukraine,
58, Petropavlivska Str., Sumy 40000, Ukraine. 
E-mail: shchokotova.o@gmail.com

In order to predict the durability and reliability of construction materials, which are subjected to irradiation and mechanical loads, it is necessary to study an influence of irradiation on change in their mechanical properties. Based on the phase field model in the framework of nonlinear elastic theory [1, 2] we have performed the three-dimensional numerical modeling of plastic flow of previously prepared samples of binary Zr-Sn alloy under neutron irradiation and mechanical loading. Cases of unirradiated and irradiated alloy under different irradiation conditions (irradiation temperature, dose rate) are considered separately. The irradiation influence on strength and plastic properties changing is studied. We consider monotonic load with constant strain rate in the form of simple shear. The simulations are implemented at high values of strain rate from  to . The strain-rate influence on the mechanical properties is studied to determine the strain-rate sensitivity of Zr-Sn alloys.
The distributions of strain, elastic energy and stress are obtained. Dynamics of the slip planes and dislocation loops are modelized. The stress-strain curves, the dependencies of the strain hardening coefficient and elastic energy on the strain at different strain rates and irradiation parameters are analyzed. Studying the irradiation influence on mechanical properties we have found that the yield strength and ultimate strength increase with the irradiation dose rate and decrease with irradiation temperature. In other words, the irradiation dose rate growth results in an increase of the resistance of Zr-Sn alloy to plastic deformation and its hardening, whereas the irradiation temperature increasing acts in opposite manner.

1.	Minami A., Onuki A. Dislocation formation and plastic flow in binary alloys in three dimensions // Phys. Rev. B.-2005.-72.-P. 100101(4).
2.	Minami A., Onuki A. Nonlinear elasticity theory of dislocation formation and composition change in binary alloys in three dimensions // Acta Materialia.-2007.-55.-P. 2375-2384.