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Aoyagi, Yoshiteru; Tsuru, Tomohito; Kaji, Yoshiyuki
Effects of Radiation on Nuclear Materials; 25th Volume (ASTM STP 1547), p.269 - 287, 2013/01
Times Cited Count:0 Percentile:0.00(Materials Science, Characterization & Testing)In this study, we construct a new crystal plasticity model considering densities of crystal defects induced by irradiation. Evolution equation of densities of imperfect dislocation loop is proposed by considering disappearance of imperfect dislocation loops originated in dislocation movement. Moreover, in order to predict increase of CRSS due to irradiation and decrease of work-hardening ratio, information of densities of imperfect dislocation loop and stacking fault tetrahedron are introduced into a hardening modulus of crystal. Value of controlling parameters operating effect of crystal defects on flow stress are decided by a MD simulation. We conduct a crystal plasticity simulation for simple tension of polycrystal using the presented model. The macroscopic stress-strain responses such as increase of yield stress and decrease of work-hardening ratio due to irradiation are numerically predicted. We investigate comprehensively the effect of behaviors of crystal defects on the mechanical property of irradiated materials and the generation of dislocation substructures depending on mechanical conditions.
Abe, Yosuke; Jitsukawa, Shiro; Okubo, Nariaki; Matsui, Hideki*; Tsukada, Takashi
Effects of Radiation on Nuclear Materials; 25th Volume (ASTM STP 1547), p.313 - 337, 2013/01
Times Cited Count:0 Percentile:0.00(Materials Science, Characterization & Testing)It is known that the mechanical properties degradation of reactor pressure vessel steels caused by neutron irradiation is partly due to the formation of nanometer-size solute and point-defect (PD) clusters. Therefore, the rationalization of radiation induced effects on the microstructure and their consequences on the material properties by developing predictive models is thus of great importance. Cluster dynamics (CD) simulation with rate equations has been used to estimate the long-term evolution of point defect clusters. We have extended the CD simulation code to allow hopping motion for all the self-interstitial atom (SIA) clusters to be mobile. Results of calculation on 316 stainless steel and -iron have been compared. The difference and underlying mechanism of microstructural evolution between austenitic stainless steel and
-iron is discussed with regard to the dose dependence.