Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre (IMWF), Universität Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart, Germany.
Institut für Funktionelle Materie und Quantentechnologien (FMQ), Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
J Chem Phys. 2018 Jul 14;149(2):024701. doi: 10.1063/1.5029887.
Effective interaction potentials suitable for Cu/δ-NiSi and Cu/β-NiSi are developed. We optimise the potential parameters of an embedded atom method potential to reproduce forces, energies, and stresses obtained from ab initio calculations. Details of the potential generation are given, and its validation is demonstrated. The potentials are used in molecular dynamics simulations of shear tests to study the interactions of edge dislocations with coherent δ-NiSi and β-NiSi precipitates embedded in a copper matrix. In spite of significantly different crystallographic structures of copper and δ-NiSi which usually result in circumvention of dislocations, we also observed cutting processes in our simulations. Dislocations cut for a specific orientation of the δ-NiSi precipitate and in some cases where dislocation loops originating from previous circumvention processes are present in the glide plane. It is found that β-NiSi precipitates have a similar effect on precipitation strengthening as δ-NiSi. Dislocations usually cut β-NiSi but increased coherency strain can lead to circumvention processes.
开发了适用于 Cu/δ-NiSi 和 Cu/β-NiSi 的有效相互作用势。我们优化了嵌入原子法势的势参数，以再现从头算计算得到的力、能量和应力。给出了势生成的细节，并验证了其有效性。该势用于剪切试验的分子动力学模拟，以研究位错与嵌入铜基体中的相干 δ-NiSi 和 β-NiSi 析出物的相互作用。尽管铜和 δ-NiSi 的晶体结构有很大的不同，通常会导致位错绕过，但在我们的模拟中也观察到了切割过程。位错会沿特定取向的 δ-NiSi 析出物切割，在某些情况下，来自先前绕过过程的位错环存在于滑移面中。结果发现，β-NiSi 析出物对沉淀强化有类似的作用。位错通常会切割 β-NiSi，但增加的相干应变会导致绕过过程。
