Kinetic Monte Carlo simulations have been performed to investigate the evolution of ordered domains in model alloys under irradiation. The alloys investigated were equiatomic binary alloys on a simple square lattice with first and second nearest-neighbor interactions, chosen so that a $2\times 2$ ordered structure is the equilibrium phase below a critical order-disorder transition temperature $T_{\mathrm{c}}$. The ratio of second to first nearest-neighbor interactions $R$ was varied from 0 to 0.45 to explore the effect of the thermodynamic frustrations induced by the proximity of the $2\times 1$ phase boundary, which occurs at $R=0.5$ for $T=0$. The atomic mixing produced by nuclear collisions was modeled by forcing the ballistic exchange of pairs of atoms at a controlled rate ${\mathrm{\Gamma }}_{\mathrm{b}}$. This disordering process competed with thermodynamic reordering, resulting in nonequilibrium steady states. Two trivial steady states were found, a disordered state at high ${\mathrm{\Gamma }}_{\mathrm{b}}$ and low $T$, and a long-range ordered state at low ${\mathrm{\Gamma }}_{\mathrm{b}}$ and low $T$. In the $R=0.45$ alloy, however, a third steady state was identified at intermediate ${\mathrm{\Gamma }}_{\mathrm{b}}$ and $T$ values, where multiple long-range ordered domains coexisted dynamically. It is shown that this state of patterning of order resulted from the coupling of the thermodynamic frustrations present in that alloy with the disorder introduced by irradiation. The practical relevance of this novel mechanism for patterning of order under irradiation is discussed in the context of recent observations of domain coexistence in irradiated ${\mathrm{Cu}}_3\mathrm{Au}$.

中文翻译：

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辐照驱动合金中有序构图的新机制

动力学蒙特卡洛模拟已被执行，以研究在辐照下模型合金中有序畴的演变。研究的合金是具有第一和第二最近邻相互作用的简单正方形晶格上的等原子二元合金，因此选择$\mathrm{2个}\times \mathrm{2个}$ 有序结构是低于临界有序-无序转变温度的平衡相 ${Ť}_{\mathrm{C}}$。第二个与第一个最近邻居的交互比率$\mathrm{[R}$ 在0到0.45之间变化，以探究由于热电偶的接近而引起的热力学挫折的影响。 $\mathrm{2个}\times \mathrm{1个}$ 相界，发生在 $\mathrm{[R}=0.5$ 为了 $Ť=0$。核碰撞产生的原子混合是通过以受控速率强迫原子对的弹道交换来建模的${\mathrm{\Gamma }}_{\mathrm{b}}$。这种无序过程与热力学重排竞争，导致非平衡稳态。发现了两个微不足道的稳态，一个处于高位的无序状态${\mathrm{\Gamma }}_{\mathrm{b}}$ 和低 $Ť$，以及处于低位的远程有序状态 ${\mathrm{\Gamma }}_{\mathrm{b}}$ 和低 $Ť$。在里面$\mathrm{[R}=0.45$ 合金，但是，在中间发现了第三稳态 ${\mathrm{\Gamma }}_{\mathrm{b}}$ 和 $Ť$值，其中多个远程有序域动态共存。结果表明，这种有序构图状态是由于该合金中存在的热力学受挫与辐射所引起的无序性的耦合所致。在最近观察到辐照域共存的背景下，讨论了这种新颖的在辐照下构图的机制的实用意义。${铜}_3金$。