高稳定性V/Cu纳米叠层材料的CARB制备和抗辐照损伤机理研究

Nanolaminar materials with high thermal stability have been evidenced to exhibit excellent anti-irradiation “self-healing” characteristics because of their rich phase interfaces that can act as effective sinks for irradiation defects. The project is mainly focused on V-based alloys that have an important fusion engineering background, and aims to explore how to improve the thermal stability and anti-irradiation properties of structural materials based on interface engineering design. Benefit from the immiscibility of V with Cu, V/Cu nanolaminar composites with different monolayer thickness (20~200nm ) and interface structures are controllably prepared by a across accumulative roll bonding (CARB) method. The effects and optimization mechanisms of monolayer thickness and interface microstructures on mechanical, thermal stability and anti-irradiation properties of the V/Cu nanolaminar composites will be carefully investigated by mechanical test, interface internal friction measurement, high energy He ion irradiation and micro-structure analysis methods. Based on different V/Cu interface structure, the atomic-scale interaction process and damage mechanisms between interface and irradiation defects under different irradiation dose are systematically studied and clarified by molecular dynamics simulation methods. The project is expected to provide an optimized CARB technique for the fabrication of high performance V/Cu nanolaminar materials and figure out the physical concept of interfacial irradiation self-healing process, which helps to provide important scientific basis on how to develop V/Cu nanolaminar materials as well as other novel anti-irradiation nano-structured materials with high strength, high thermal stability.

纳米叠层材料因含有丰富的、可作为辐照缺陷“捕获阱”的相界面而表现出优异的抗辐照性能。本项目以聚变堆候选结构材料V基合金为研究对象，针对如何基于相界面优化结构材料的热稳定性和抗辐照等问题展开研究。利用金属钒和铜的非固溶特性结合正交累积叠轧方法(CARB)制备不同层厚 (20~200nm)、界面结构可控的高热稳定V/Cu纳米叠层材料，并综合力学、界面内耗、He离子辐照和微结构分析等方法研究膜厚、界面结构等对其热稳定和抗辐照等性能的影响和机理；构建几种典型V/Cu相界面结构，采用分子动力学方法 (MD) 研究不同辐照条件下相界面与缺陷的相互作用过程，从原子尺度阐明纳米叠层材料抗辐照损伤的微观机制。项目预期可提供高性能V/Cu纳米叠层材料的最优CARB制备工艺、建立相界面辐照损伤自修复的物理图像，为基于界面工程研发具有高强、高热稳定和抗辐照等综合性能的V/Cu等新型纳米结构材料提供科学依据。

纳米叠层材料中含有高密度、可作为辐照缺陷“捕获阱”的相界面，因而具有优异的抗辐照“自修复”性能。项目研究主要以核能结构材料V合金为研究对象，基于正交累积叠轧方法(CARB)制备V/Cu及其相关体系（Ta/Cu、Nb/Cu、Fe/Cu）纳米叠层材料，并系统研究叠层膜厚、界面结构等对复合材料热稳定和抗辐照等性能的影响和机理，所取得的主要研究结果如下：.（1）基于发展、改进的正交累积叠轧焊(CARB)技术并结合中间退火工艺，成功制备了层厚分布从微米至纳米尺度（最小单层厚度25 nm）的系列Cu/V纳米叠层膜块材，其内部层状结构连续、完整，层厚均匀，界面清晰、平直, 并包含高体积分数的相界面和低体积分数的晶界；相关材料制备工艺拓展至Ta/V、Fe/Cu、Nb/Cu等不同叠层膜体系，可为系统研究纳米叠层材料的相界面结构、热力学和抗辐照稳定性奠定材料制备工艺基础。.（2）系统研究了CARB-V/Cu纳米叠层膜块材及Ta/V、Fe/Cu等不同叠层膜体系的力学性能和热稳定性，研究结果表明：纳米叠层膜块材兼具高强度和高热稳定性，突破了传统纳米结构材料强度-稳定性不能兼顾的关系，纳米叠层膜块材的强度（硬度）达到原始材料的3~5倍，其机制被认为主要与高密度、高稳定的相界面结构相关。.（3）基于不同剂量的He离子辐照系统研究了CARB-Cu/V纳米叠层膜块材及Ta/V、Fe/Cu、Nb/Cu等不同叠层膜体系的抗辐照损伤性能，结果表明：纳米叠层材料由于具有高稳定的相界面和自修复特性，而表现出高抗辐照稳定性，相关研究结果可为后续研发具有高强、高热稳定和抗辐照等综合性能的新型纳米结构材料提供科学依据。.（4）项目执行过程中，共发表基金标注SCI论文共18篇，其中，与项目直接相关的论文7篇，相关论文发表在Acta Materialia, Scripta Materialia, Journal of Nuclear Materials等国际重要期刊上，培养博士研究生和硕士研究生，共6名，其中，4名博士生顺利毕业，较好地完成了项目的预期研究目标。