层状金属结构材料原子尺度界面结构与性能

Atomistic scale interfacial structure and properties of layered metal structural materials

通常纳米晶金属材料晶界上原子呈无序排列,晶界能高,因此纳米晶金属材料的热稳定性很差。研究发现通过界面调制作用制备纳米多层复合金属材料能够显著提高材料的热稳定性以及力学和抗辐照损伤等综合性能。本文综述了通过叠加轧制法制备得到的多层Cu-Nb复合板材的界面结构与性能。由于材料内部高密度半共格界面的调控作用,此层状材料具有优异的热稳定性和抗辐照损伤性能。例如,经500℃退火1 h此层状材料硬度基本不变。同时,本文对退火引起的层状材料的结构和力学性能演化机理做了系统分析。此外,辐照研究发现当辐照剂量低时,界面的局部高能区域为空洞形核提供了有效位点;当辐照剂量高时,界面可以显著抑制空洞的生长并调控空洞分布特征。此结果为通过合理设计界面结构使材料同时实现高热稳定性,高耐辐照和优异的力学性能提供了依据。

In general,disordered arrangement of atoms in the grain boundaries of nanocrystalline metallic materials makes their interface energy very high,resulting in poor thermal stability of such materials.It is proposed that the comprehensive properties of the materials can be significantly improved in metallic multilayer composites owing to interface effects.In this paper,the interfacial structure and properties of multilayer Cu-Nb composite plates prepared by accumulative roll bonding are reviewed.Due to the high-density semi-coherent interfaces inside the materials,the materials have excellent thermal stability and irradiation damage resistance.After annealing at 500℃for 1 h,the hardness is basically unchanged.Meanwhile,the structural and mechanical properties evolution mechanism of layered materials induced by annealing are systematically analyzed.As for irradiation damage resistance,it is found that when the irradiation dose is low,the local high interfacial energy regions of the interfaces can provide nucleation sites for voids;when the irradiation dose is high,the interface can significantly inhibit the growth of voids and regulate the distribution of voids.The findings in this work provide a basis for the reasonable design of interface structure to achieve high thermal stability,high radiation resistance and excellent mechanical properties.