Establishing the Relation Between Properties, Microstructures, and Processing Parameters in Innovative Eccentric Friction Based Additive Manufacturing

附加制造(AM)技术的应用不断增加，因为它们降低了制造成本，消除/减少了对后续加工和组装的需求。快速凝固会影响材料熔融的AM零件的性能，进而影响材料的显微组织。尽管进行了广泛的研究，但根本性的挑战仍然存在，包括凝固引起的气孔、大的温度梯度、残余应力、不均匀的晶粒结构和热裂。因此，正在开发包括添加搅拌摩擦制造在内的固态AM方法，将逐层AM技术与固态搅拌摩擦焊接相结合来解决这些问题。然而，这项技术通常仅限于制造大型近形零件和用于大规模应用的选择性区域增强。该研究项目旨在开发一种配备加热器的新型偏心摩擦AM技术，允许小直径线材的进料以比传统的添加摩擦搅拌制造更高的精度更窄地沉积AM层。因此，进给材料的整个横截面以均匀的线速度滑动到衬底上，并由于进给材料的偏心而导致摩擦加热，从而沉积出缺陷最少、组织和性能均匀的AM层。该实验装置还将应用于包含蓝宝石衬底和高焦深显微镜的原位配置，以观察和研究AM沉积过程中变形区的详细变形机制。本研究将系统地研究材料变形和向基材/层转移的微观机制及其对沉积AM层的组织、孔洞/缺陷、力学性能、腐蚀和耐磨性的影响，以建立AM零件的工艺参数与性能之间的关系。综上所述，研究结果将用于通过改善金属AM工艺的组织(通过熔覆层的原位变形)和控制应变和应变速率(通过FM的织构、转速、偏心距、温度和进给率)来降低成本和提高效率和质量。该计划将培训9名高素质人才。

The application of additive manufacturing (AM) technologies continues to increase as they reduce manufacturing costs and eliminate/reduce the need for subsequent machining and assembly. The properties of AM parts involving the melting of materials are influenced by rapid solidification, which affects the microstructure. Despite extensive research, fundamental challenges persist, including solidification induced porosities, large thermal gradients, residual stresses, non-homogeneous grain structure, and hot cracking. Therefore, solid-state AM methods, including additive friction stir manufacturing, are being developed, which combine layer-by-layer AM technology with solid-state friction stir welding to address these issues. However, the technique is typically limited to the fabrication of large near-shaped parts and selective area reinforcement for large-scale applications. This research program aims to develop a novel eccentric friction-based AM technique equipped with heaters, allowing feed of small diameter wire materials for narrower deposition of AM layers with higher precision than conventional additive friction stir manufacturing. Therefore, the entire cross-section of the feed material slides against the substrate with a uniform linear velocity and contributes to frictional heating due to the eccentricity of the feed material, depositing AM layers with minimum defects and uniform microstructure and properties. The experimental setup will also be applied to an in-situ configuration incorporating a sapphire substrate and a high depth-of-focus microscope to observe and study the detailed deformation mechanisms in the deformation zone during AM deposition process. This research will systematically study the micromechanisms by which the material deforms and transfers to the substrate/layers and their effects on the microstructure, the porosity/defects, the mechanical properties, corrosion, and wear resistance of the deposited AM layers to establish the relationships between the process parameters and properties of AM Parts. In summary, the results will be used to reduce the cost and increase the efficiency and quality of the metal AM processes by improving the microstructure (through in-situ deformation of the deposited layer) and controlling the strain and strain rate (through texturing, rotational speed, eccentricity, temperature and feed rate of the FM). The program will train nine highly qualified personnel.