Northwest Institute for Nonferrous Metal Research, Xi'an Shanxi 710016, China.
Nano Structural Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Sci Rep. 2017 Jan 6;7:40039. doi: 10.1038/srep40039.
Multifunctional materials with more than two good properties are widely required in modern industries. However, some properties are often trade-off with each other by single microstructural designation. For example, nanostructured materials have high strength, but low ductility and thermal stability. Here by means of spark plasma sintering (SPS) of nitrided Ti particles, we synthesized bulk core-shell structured Ti alloys with isolated soft coarse-grained Ti cores and hard Ti-N solid solution shells. The core-shell Ti alloys exhibit a high yield strength (~1.4 GPa) comparable to that of nanostructured states and high thermal stability (over 1100 °C, 0.71 of melting temperature), contributed by the hard Ti-N shells, as well as a good plasticity (fracture plasticity of 12%) due to the soft Ti cores. Our results demonstrate that this core-shell structure offers a design pathway towards an advanced material with enhancing strength-plasticity-thermal stability synergy.
具有两种以上优良性能的多功能材料在现代工业中被广泛需求。然而，一些性能往往通过单一的微观结构设计相互制约。例如，纳米结构材料具有高强度，但延展性和热稳定性低。在这里，通过氮化钛颗粒的火花等离子烧结（SPS），我们合成了具有孤立软粗晶粒钛核和硬 Ti-N 固溶体壳的整体核壳结构钛合金。核壳钛合金表现出与纳米结构相当的高屈服强度（约 1.4 GPa）和高热稳定性（超过 1100°C，熔点的 0.71），这归因于硬 Ti-N 壳，以及由于软钛核而具有良好的塑性（断裂塑性为 12%）。我们的结果表明，这种核壳结构为增强强度-塑性-热稳定性协同作用的先进材料提供了一种设计途径。
