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

增材制造（AM）技术的应用持续增加，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。涉及材料熔化的AM部件的性能受到快速凝固的影响，这影响了微观结构。尽管进行了广泛的研究，但基本的挑战仍然存在，包括凝固诱导孔隙、大的热梯度、残余应力、非均匀晶粒结构和热裂纹。因此，正在开发包括增材摩擦搅拌制造的固态AM方法，其将逐层AM技术与固态摩擦搅拌焊接联合收割机结合以解决这些问题。然而，该技术通常限于制造大型近形零件和大规模应用的选择性区域加固。该研究计划旨在开发一种新型的偏心摩擦基AM技术，配备加热器，允许进给小直径线材，以获得比传统增材摩擦搅拌制造更高精度的AM层沉积。因此，供给材料的整个横截面以均匀的线速度抵靠基板滑动，并且由于供给材料的偏心率而有助于摩擦加热，从而沉积具有最小缺陷和均匀的微观结构和性质的AM层。实验装置也将被应用到一个原位配置，包括一个蓝宝石衬底和一个高焦深显微镜观察和研究在AM沉积过程中的变形区的详细变形机制。本研究将系统地研究材料变形和转移到基体/层的微观机制及其对沉积AM层的微观结构、孔隙率/缺陷、机械性能、腐蚀和耐磨性的影响，以建立AM部件的工艺参数和性能之间的关系。总之，结果将用于通过改善微观结构（通过沉积层的原位变形）和控制应变和应变速率（通过FM的纹理化、旋转速度、偏心率、温度和进给速率）来降低金属AM工艺的成本并提高金属AM工艺的效率和质量。该计划将培养9名高素质的人才。

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.