Nanoscale precipitation is one of the most widely used microstructural tools to manipulate the properties of metallic alloys, and especially to reach high strength. Optimal microstructures are reached through complex solid state phase transformations involving non-isothermal heat treatments, metastable phases, complex chemistry, non-equilibrium vacancies, and interaction with structural defects. These phase transformations are controlled by an interplay between thermodynamics and kinetics, resulting through nucleation, growth and coarsening, in a large variety of precipitation trajectories that depend on both alloy chemistry and processing. Progress in both experimental characterization and modeling has tremendously improved the knowledge and description of these processes. The purpose of this overview is to describe the current level of understanding of precipitation kinetics, starting from the relatively simple situation of homogeneous precipitation of dilute coherent phases and including different levels of additional complexity regarding the diffusion mechanism, the effect of finite volume fraction, the effect of particle shape, the competitive multi-phase precipitation, the heterogeneous nucleation, and the non-isothermal effects.

纳米级沉淀是最广泛使用的微观结构工具之一，用于控制金属合金的性能，尤其是达到高强度。通过涉及非等温热处理、亚稳态相、复杂化学、非平衡空位以及与结构缺陷的相互作用的复杂固态相变，达到最佳微观结构。这些相变由热力学和动力学之间的相互作用控制，通过成核、生长和粗化，在取决于合金化学和加工的多种沉淀轨迹中产生。实验表征和建模方面的进展极大地改进了对这些过程的知识和描述。