Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration
Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration
复制标题
DOI：
10.1063/1.4928627
复制
发表时间：
2015-08-17
影响因子：
4
通讯作者：
Schaaf, P.
中科院分区：
文献类型：
--
作者：
Herz, A.;Friak, M.;Schaaf, P.
固态去湿用于通过快速热退火技术从薄的 Au/Ni 双层中制造过饱和的亚微米尺寸的 Au-Ni 固溶体颗粒。通过随后在高温下的退火，研究了此类颗粒中的相分离的平衡晶体（或武尔夫）形状。研究发现，平衡粒子的{100}面富含Ni，{111}面富含Au。这两个相都通过量子力学计算与误差减少方案相结合来考虑，该方案是为了补偿可靠地描述金和镍的交换相关势的缺失而开发的。然后，观察到的相配置与富金相和富镍相的强各向异性弹性能的最小化相关，并导致相当独特的纳米粒子复合状态，其特征在于整个多面表面上对外延应变的弹性响应值几乎一致。当采用插值实验弹性常数时评估双轴弹性模量也得出相同的结论。这项工作展示了研究介观尺度物理冶金特征的有用途径。 (C) 2015 AIP 出版有限责任公司。
Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that {100} faceting planes of the equilibrated particles are enriched with Ni and {111} faces with Au. Both phases are considered by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. The same conclusion is yielded also by evaluating bi-axial elastic moduli when employing interpolated experimental elastic constants. This work demonstrates a useful route for studying features of physical metallurgy at the mesoscale. (C) 2015 AIP Publishing LLC.