冷喷涂增材制造AlSi8Cu3材料的基础问题研究

Aiming at a potential application for cylinder of automobile engine, Additive Manufacturing for an aluminum alloy and its composite will be investigated with AlSi8Cu3 and Al2O3 powders as primary phase and enhanced phase by Cold Spray, for the small heat input and no oxidation, grain growth, phase transformation during depositing process. Effects of grain size (micro crystal and nanocrystalline) of aluminum alloy powder, and the powder size, size distribution and content of the enhanced phase Al2O3, on the structure and strength of the aluminum alloy and the composite will be evaluated. Then, the behaviors of deformation and bonding during the impact process of the AlSi8Cu3 particles will be simulated through finite element simulation method. The combination mechanism between particles of the aluminum alloy, as well as between the aluminum alloy phase and the ceramic phase, and the forming mechanism of the materials will be revealed by the analysis of microstructure and the mechanical properties of the materials. By analyzing stress in the composite materials, gradient AlSi8Cu3-Al2O3composite materials will be designed and fabricated. The effect and mechanism of heat treatment on thermal stability and grain growth in AlSi8Cu3 and AlSi8Cu3/Al2O3 composite will be also evaluated. It is the purpose of this project to find the solution for the key technology problem in 3D printing based on Cold Spray, to obtain the controlling method for structure and properties of the rapid prototyping materials, to provide theory basis for the metal-ceramic composite by Cold Gas Dynamic Spray- Additive Manufacturing .

本项目瞄准汽车发动机系统的汽缸体应用，利用冷喷涂热输入小以及不会产生氧化、晶粒长大和相变的优点，以AlSi8Cu3粉末和Al2O3颗粒作为母相和增强相，开展AlSi8Cu3材料及与Al2O3复合材料增材制造技术研究。研究材料中合金晶粒尺寸以及增强相颗粒尺寸、分布及含量对铝合金及其复合材料组织结构及强度的影响规律；通过有限元模拟，研究颗粒在撞击过程的变形和结合行为，结合实验结果讨论沉积的铝合金颗粒自身、与陶瓷增强相之间的结合行为，揭示低温沉积过程的材料成型机制，阐明冷喷涂工艺对块体材料力学性能的影响规律。通过分析增强相对复合材料应力状态的影响，设计制备AlSi8Cu3/Al2O3梯度复合材料。讨论铝合金及其复合材料后期热处理及使役过程中的热稳定性及晶粒长大机制。获得该类材料冷喷涂增材制造的关键工艺及组织性能控制方法，为利用冷喷涂技术实现金属材料和金属陶瓷复合材料增材制造提供理论依据。

本项目瞄准汽车发动机系统的汽缸体应用，利用冷喷涂热输入小以及不会产生氧化、晶粒长大和相变的优点，以AlSi8Cu3粉末和Al2O3颗粒作为母相和增强相，开展AlSi8Cu3材料及与Al2O3复合材料增材制造技术研究。研究材料中合金晶粒尺寸以及增强相颗粒尺寸、分布及含量对铝合金及其复合材料组织结构及强度的影响规律；通过有限元模拟，研究颗粒在撞击过程的变形和结合行为，结合实验结果讨论沉积的铝合金颗粒自身、与陶瓷增强相之间的结合行为，揭示低温沉积过程材料成型机制，阐明冷喷涂工艺对块体材料力学性能的影响规律。通过分析增强相对复合材料应力状态的影响，设计制备AlSi8Cu3/Al2O3梯度复合材料。讨论铝合金及其复合材料后期热处理及使役过程中的热稳定性及晶粒长大机制。获得该类材料冷喷涂增材制造的关键工艺及组织性能控制方法，为利用冷喷涂技术实现金属材料和陶瓷颗粒增强金属基复合材料的增材制造提供理论依据。项目获得的主要成果如下：.（1）研发了一种新型的冷气动力喷涂增材制造装置；.（2）获得冷喷涂制备的铝合金块体和铝合金/陶瓷复合块体材料技术，采用此方法制备的AlSi8Cu3/Al2O3复合材料力学性能（230MPaUTS，6% Elf)超过了铸造AlSi8Cu3材料（227 MPa UTS，1.52 Elf）；.（3）揭示冷喷涂低温固态沉积过程AlSi8Cu3材料的成型机制以及硬质颗粒Al2O3对AlSi8Cu3/Al2O3 复合材料性能的影响规律；.（4）在SCI 收录的国内外重要学术期刊上发表论文15 篇，申请专利2 项；.（5）培养硕士研究生2 名，博士研究生2 名。