Fabrication and investigation of nano particle, fibre and nanotube multiscale reinforced aluminium matrix composites

自然资源枯竭和环境问题日益严重是当前的主要挑战。此外，机动性、性能、速度和安全性的提高是不断增长的需求。这些挑战使高性能轻质材料成为当今技术的基本概念，特别是在汽车、航空航天和国防领域。****因此，拟议的研究计划旨在开发轻质、梯度、多尺度增强铝基复合材料，使用纤维、纳米管和纳米颗粒。一种新型的、经济的层压板挤压铸造技术将被开发出来。所需的挤压压力将主要利用设置组件的热膨胀差异来实现，几乎不需要压力机或其他压实设备。这使得技术向工业转移变得容易。在这种技术中，薄的预制铝绿层熔化并在短距离内渗透到夹在中间的纤维层中，从而最大限度地降低温度和压力降，这是使用3D预成型器进行标准液体渗透时经常遇到的挑战。研究将重点放在碳纤维作为主要增强材料，而碳和氮化硼纳米管将作为纤维-基体界面的增强材料来改善键合。通过机械合金化和粉末冶金，主要使用Al2O3纳米颗粒将铝基体进一步硬化。功能梯度将通过改变复合材料厚度上的增强剂浓度来引入。这将通过将性能与组件之间的特定负载分布相匹配来提高复合材料的效率。复合材料将使用光学和扫描电子显微镜以及x射线衍射进行表征。弯曲和冲击试验将用于研究强度，刚度，抗冲击断裂和破坏模式。为了指导进一步的改进，将使用基于物理、神经网络、有限元和无网格建模建立制造参数、微观结构和力学性能之间的关系。****作为世界第三大原铝生产国，拟议的研究将对加拿大产生重大经济影响，年产量估计为320万吨，2017年出口总额超过127亿美元，仅原铝生产就有超过10,000个直接就业岗位。它旨在扩大加拿大生产增值铝产品的能力。重点是为汽车、航空航天和国防领域的高要求应用开发新型复合材料。近无压制造旨在匹配制造实践，这将促进工业采用并增加金属基复合材料的技术影响。总体而言，高性能重量比将有助于提高效率、机动性和安全性，并减少能源消耗和对环境的影响

Depleting natural resources and increasing environmental concerns are current major challenges. In addition, increases in mobility, performance, speed and safety are constant demands. These challenges have made high-performance lightweight materials fundamental concepts of today's technology, particularly in automotive, aerospace and defence.****Therefore, the proposed research program aims at developing lightweight, gradient, multiscale reinforced aluminium matrix composites using fibres, nanotubes and nanoparticles. A novel and cost efficient laminate squeeze casting technique will be developed. The required squeeze pressure will be achieved using primarily differences in thermal expansions of the set-up components with little to no need for presses or other compaction equipment. This enables easy technology transfer to industry. In this technique, thin pre-fabricated aluminium green layers melt and infiltrate the sandwiched fiber layers over short distances, minimising temperature and pressure drops that are challenges often encountered in standard liquid infiltration using 3D preforms. Research will focus on carbon fiber as primary reinforcement, while carbon and boron nitride nanotube will be studied as reinforcement of the fiber-matrix interface to improve bonding. Additional hardening of the aluminium matrix will be achieved using primarily Al2O3 nanoparticles introduced in the greens by mechanical alloying and powder metallurgy. Functional gradients will be introduced by varying the concentrations of reinforcements across the composite thickness. This will increase the efficiency of the composites by matching properties to specific load distributions across components. The composites will be characterised using optical and scanning electron microscopy as well as X-ray diffraction. Bend and impact testing will be used to study the strength, stiffness, impact fracture resistance and failure modes. To guide further improvements, relationships will be established between fabrication parameters, microstructure, and mechanical properties using physics-based, neural network, finite element and meshless modelling.****The proposed research will have a major economic impact for Canada as the world's third largest producer of primary aluminium, with an annual output estimated at 3.2 million tonnes, exports totaling over $12.7 billion in 2017, and over 10,000 direct jobs for primary aluminium production alone. It aims at expanding Canada's capacity to manufacture value-added aluminium products. The emphasis is on new composites for highly demanding applications in automotive, aerospace and defence. Near pressureless fabrication aims at matching manufacturing practices which will facilitate industry adoption and increase the technological impact of metal matrix composites. Overall, the targeted high performance-to-weight ratios will contribute to increased efficiency, mobility and safety as well as to reduced energy consumption and environmental impact.***