Fig. 1. Changes in the number of primary knocks-on defects in nickel: (a) <135>, (b) <122>, and (c) <100> distinct crystal orientations under different temperatures and various PKA energies as a function of time

Fig. 2. Evolution of time-dependent defects in nickel at 300 K with PKA direction of <135> (a) Defect evolution and arrangements in nickel with PKA energy of 20 keV; insets (a2~a5) are the typical defect arrangements during the four typical stages (collision, thermal peak, quenching, and annealing) of the displacement cascades. Defect distributions during the thermal peak stage (b, c, d) and annealing stage (b2, c2, d2) of nickel with PKA energies of 2 keV, 5 keV, and 10 keV (red sphere represents vacancy, and blue sphere represents interstitial atoms) (color online)

Fig. 3. Comparison of the distribution of defects in nickel at 300 K and 500 K in <122> (a, a2, b, b2) and <100> (c, c2, d, d2) directions with PKA energy of 20 keV (red sphere represents vacancy, whereas the blue sphere represents interstitial atoms) (color online)

Fig. 4. (a) Defect number evolution of nickel in the <135> direction at various temperatures when the PKA energy is 10 keV, (b) Variation of steady-stage defect number of nickel at different temperatures and bombarding directions with PKA energies

Fig. 5. Variation curve of defect numbers of iron (a) and tungsten (b) with various PKA energies and bombarding in the <135> direction. (c) Steady-state defect numbers of iron and tungsten as a function of PKA energy and in the <135> direction. Inset (a2) is the secondary displacement cascade, whereas inset (b2) is the partially enlarged view of (b).

Fig. 6. Thermal peak and steady-state defect distribution in (a, a2) iron and (b, b2) tungsten at the thermal spike and annealing stages, respectively, in the <135> direction when the simulated temperature is 300 K and PKA energy is 20 keV

Fig. 7. Variations of defect recombination (a) and survival (b) rates of nickel, iron, and tungsten with PKA energy at 300 K and 500 K and in the <135> direction

Fig. 8. Comparison of defect numbers of nickel, iron, and tungsten calculated by using various methods

Table 1. Atomic interactional potentials of nickel, iron, and tungsten metal and the calculated lattice parameters at various temperatures

Table 2. Material parameters of nickel, iron, and tungsten used for the Arc-dpa model simulation