功能驱动的仿生结构多材料构件激光增材制造基础研究

The realization of multi-material distribution and multiple functions in the complex integral components is a new development direction of additive manufacturing technology. Nevertheless, due to the constraint of multi-function, the coupling rules of multi-scale structure and multi-material distribution are complex, causing a significant difficulty in achieving the goal of multi-function for the integral components. Considering the extremely harsh outer space environment and the multi-functional requirements of Mars Lander such as heat insulation/heat protection, shock absorption/impact resistance, and anti-radiation hardening, this project obtains the biological inspiration from the shell of Crysomallon squamiferum, the bubble of water spider, and the lobster eyes. The mapping relation and corresponding scale effect between bionic structures and functions are studied and the topology optimization design methods for the macro/micro large scale-span bionic functional structures are established. Based on the multi-material design of the ceramic/Ti-alloy laminated composite material and the carbon nanotubes (CNTs) reinforced Al-based nanocomposite material, the multi-scale interface effect and function regulation mechanism of laser additive manufactured multi-material components are studied. The synergistic evolution mechanisms among the microstructure of multi-material during laser processing (microscale), the melting behavior of powder particles (mesoscale), and the stress and deformation of bionic structures (macroscale) are established, so as to disclose the macro/micro multi-scale coordinated control principles of structures and properties. The evaluation, verification and integrated optimization methods for functions of bionic-structured multi-material components are proposed. Combined with the application background, the exploration of laser holistic manufacturing of multi-functional components is performed, providing key technology and scientific theory for the realization of material - structure - function integration for bionic components.

复杂整体构件实现多材料布局及多功能化是增材制造技术新的发展方向；但多功能约束下多尺度结构与多材料分布的耦合规律复杂，造成整体构件多功能化目标实现困难。本项目面向空间严苛环境下火星探测着陆器对隔热/防热、减震抗冲击、抗辐射加固等功能需求，基于鳞脚蜗牛壳、水蜘蛛水泡、龙虾眼等生物启迪，研究仿生结构与功能的映射关系及尺度效应，建立宏/微大跨尺度仿生功能结构拓扑优化设计方法；基于陶瓷/钛合金层状复合材料、碳纳米管增强铝基纳米复合材料等多材料设计，研究激光成形多材料构件的多尺度界面效应及功能调控机制；建立激光作用下多材料显微组织（微观）、粉末颗粒熔化行为（介观）、仿生结构应力与变形（宏观）的协同演变机制，揭示宏/微多尺度协调的形性控制原理；建立仿生结构多材料构件功能评估验证及集成优化方法，结合应用背景开展多功能构件激光整体制造工艺探索，为实现仿生构件的材料—结构—功能一体化提供关键技术及科学理论。

本项目以航空航天领域复杂整体金属构件多功能化为目标，面向轻量化、承载、隔热/防热、减震抗冲击等多功能需求，系统开展了仿生金属结构设计与优化、多材料激光成形及界面调控、激光增材制造控形与控性以及典型功能验证与应用评价等方面研究，实现了基于仿生概念的多材料构件激光增材制造的结构—材料—工艺—性能一体化调控。主要研究成果如下：（1）构建了基于仿生概念的宏/微跨尺度功能结构优化设计及增材制造方法，包括：面向轻量化及减震/抗冲击功能，建立了仿水蜘蛛网壳结构、仿甲虫翅鞘双曲面结构、仿螳螂虾尾节多层级波纹结构等多杆类、点阵类、波纹类仿生结构优化设计与增材制造方法；面向承载和隔热/防热功能，揭示了仿挪威雪杉承载-热防护梯度多孔结构激光增材制造一体化成形机制；面向形状记忆功能，提出了NiTi合金仿马鞍藻鞍状点阵结构、仿黄道蟹蟹钳微孔结构等仿生设计与增材制造功能构筑方法；面向光聚焦功能，构建了激光增材制造仿龙虾眼异形周期性多通道微阵列结构编译机制及功能构筑原理。（2）揭示了轻合金基多材料仿生构件激光增材制造跨尺度工艺调控及优化机制，包括：发现了激光增材制造过程中刮刀、喷嘴等粉末输运装置与粉末颗粒相互作用规律，揭示了介观尺度粉末-激光瞬态作用及能量吸收传导机制，建立了轻合金基多材料激光增材制造熔池熔体润湿铺展行为的局部能场调控方法，明晰了多材料激光粉末床熔融成形过程强化相组织和异质界面应力演变规律与控制方法。（3）明晰了激光增材制造陶瓷/金属层状复合及金属基纳米复合多材料成形工艺及性能，包括：揭示了仿生层状陶瓷/金属多材料、碳纳米管改性钛基/铝基多材料、梯度界面金属基复合材料激光增材制造形性调控及强韧化机制，建立了高性能金属基多材料构件的界面结构–凝固组织–激光工艺–力学性能的一体化调控方法；建立了稀土原位改性高强铝合金、陶瓷改性金属基复合材料的承载/耐腐蚀/超疏水/高温抗氧化等多功能一体化激光增材制造方法，明晰了激光打印参数及能量密度、成形显微组织特征及各向异性、熔池润湿行为及表面形貌等对激光成形件多功能集成的作用规律。本项目构筑了多功能多材料仿生构件的材料–结构–性能一体化增材制造的科学原理、实现路径与调控方法。