纳米晶"双超过饱和固溶"薄膜的结构演化与强化机制

The dual-supersaturated solid solution films, exhibiting both substitutional and interstitial features, present significant nanograin refining and strengthening effects in lower solute content with high stablity, and show broad application prospect and scientific value. This project intends to reveal the regularity of microstructure formation, evolution and mechanical behavior for dual-supersaturated solid solution films through comparative research between dual-supersaturated solid solution films and the substitutionally /interstitially supersaturated solid solution films. Aiming at the difficulty in distinguishing the strengthen role of different factor in nano crystalline solid solution, the project innovatively uses a two-dimensional nano-multilayers structure as a experimental simulation sample to isolate each factor and reveal the strengthen effect of the nanometer grain size and solute content, grain boundary properties and width, and other factor individually. Based on the reasearch results, the project will propose the design and preparation principle for this kinds of materials. The results of the project could theoretically support the further investigation and industrial application of dual-supersaturated solid solution films. It is more scientific valuable that the effects of each microstructural factor revealed in this project for nanocrystalline solid solution strengthening.

兼具置换和间隙两种类型的"双超过饱和固溶"薄膜在较低的溶质含量下就呈现出晶粒纳米化和力学性能显著提高的效果并具有很高的稳定性，展示出广阔的应用前景和研究价值。 项目拟采用双超过饱和固溶薄膜与置换型、间隙型单超过饱和固溶薄膜的对比研究，揭示超过饱和固溶薄膜微结构形成、演化和力学行为的规律。针对纳米晶固溶体强化机制研究中难以区分各强化因素作用的瓶颈问题，创新性地采用二维结构纳米多层膜实验模拟的方法,"孤立"出纳米晶的尺寸、溶质含量以及晶界的性质和宽度等微结构因素进行研究，揭示它们各自对薄膜强化的作用。在此基础上提出双超过饱和固溶薄膜材料设计和制备的原则。 项目的成果可为纳米晶双超过饱和固溶薄膜的进一步研究和工业应用提供理论支持。所揭示的各微结构因素在纳米晶固溶体强化中的作用更具科学价值。

气相沉积的超过饱和固溶薄膜时是一条获得优异性能表面材料的有效途径，项目针对现有对超过饱和固溶薄膜的研究主要集中在置换型固溶的合金体系中，材料体系较为单一，以及对薄膜微结构特征和强化原因揭示不够充分的现状，项目研究了三类不同超过饱和固溶薄膜的结构特征和强化效果以及各微结构因素在强化中的作用，主要成果体现在：.1.揭示了具有置换固溶特征的Al-Ti、间隙固溶特征的Al-B合金薄膜以及兼具置换和间隙固溶特征的Al-TiB2、Al-TiC复合薄膜的微结构特征和演化规律，并比较了它们的强化效果。.2.采用高溶质含量非晶层分隔低溶质含量晶体层的二维结构多层膜实验模拟方法，揭示了晶粒尺寸、晶内溶质含量以及晶界的成分和宽度四个主要的微结构因素在纳米晶合金强化中的作用、相对权重和变化规律；结合与三维结构纳米晶薄膜的对比，获得基于各微结构因素作用规律的纳米晶合金薄膜强化机制和强度增量计算公式。.这些研究成果在超过饱和固溶薄膜材料体系拓展，微结构特征揭示和主要微结构因素强化作用的揭示等方面取得了新进展。.项目发表论文12篇，其中SCI收录11篇，培养博士生3名，硕士生6名。