微纳米共晶层状合金微观力学性能及辐射微缺陷影响的研究

Nanolayered Cu-Ag eutectic alloy is a potential structural material in aerospace application because of its high strength/hardness、high radiation tolerance and adjustable performances. The remarkable properties can be attributed to the large area of nanoscale heterogeneous interfaces between Cu and Ag metals. However, the interface-dominated deformation mechanism of Cu-Ag nanolayers is still not well-investigated. While the radiation damage, which accumulated at the interfaces, may significantly affect the microscale deformation behavior of the materials. In this project, systematically molecular dynamic simulation is applied to investigate interaction of Cu-Ag interface, as well as microstructure factors of Cu-Ag nanolayers that may affect its mechanical behaviours. We will also use atomistic simulations and comparison experiments to examine the effect of irradiation damage on Cu-Ag nanolayers microstructure evolution. Lastly, a field projection method is applied to construct the continuum traction field of Cu-Ag interfaces. The traction field is implemented in a finite element model to predict the emission and transmission of dislocation from Cu-Ag interface. These studies give a thorough understanding on microstructure evolution mechanism of nanolayered Cu-Ag eutectic alloy, thus provide theoretical support on future application of this material. The traction field model can be extended to other heterogeneous interfaces and become general representatives for all atomic interfaces.

由于在微纳米尺度具有高密度大面积的异质相界结构，以铜-银系统为代表的共晶微纳米层状合金具有高强度/硬度、抗辐射与性能可调控等优点，是一种潜在的航天领域防辐射结构材料。目前人们对于这种合金材料的微观结构演化规律和辐射引入的相界缺陷的影响尚缺乏全面系统的认识。在本项目中，申请人拟通过分子动力学模拟阐明铜-银异质相界不同结构多种载荷下的微变形反应机理，揭示决定铜-银共晶微纳米层状合金微观力学性能的关键结构因素。模拟与实验相结合，分析铜-银相界微缺陷对共晶微纳米层状合金微观结构演化机制的影响。同时，建立铜-银异质相界连续张力场模型，预测相界微变形反应。这项研究将有助于深入认识抗辐射服役过程中铜-银共晶层状合金的微观变形机理，为材料的微观结构设计与优化提供理论依据。张力场模型也可以扩展到一般异质相界的分析当中，获得对原子界面的连续一般化表征方法。

铜-银纳米层状合金为代表的微纳米铜合金具有优异的力学性能，是一种潜在的航天领域防辐射结构材料。通过使用分子动力学方法，本项目研究了铜-银合金在多种微观界面影响下的力学性能；仿真了铜-银合金在辐射冲击下的缺陷产生过程及缺陷带来的力学性能改变。同时，通过不同温度下的力学实验与疲劳实验，获得了铜合金的性能参数曲线，进而构建了宏观弹塑性本构模型，并应用于仿真计算火箭推力室铜合金内壁面的寿命与可靠性。最后，为了探索将微观分子模拟结果与宏观力学模型的结合，项目以镍基单晶高温合金作为研究对象，通过分子动力学方法，模拟了其位错生成与强化机制，跨尺度构建了镍基单晶高温合金宏观笩化热力学模型。本项目所得到的结论对于铜银纳米层状合金在抗辐射领域的应用以及镍基单晶高温合金的抗笩化应用均具备重要的工程指导意义。