Experimental and numerical investigations on locally foamable extrusions for additive manufacture of functional hybrid components

拟议项目的主要目标是生产由挤压铝型材组成的混合功能部件，这些铝型材部分由增材制造的聚合物定制。在这种情况下，在金属和聚合物的不同材料类别之间成功地创建高质量的粘合仍然是一个关键的挑战。因此，应在本提案中开发一种新的工艺方法，这将使挤出型材表面能够局部发泡。然后，铝型材的外围区域中的开孔结构将提供压痕和底切，以通过形状闭合在聚合物部件和金属表面之间建立牢固的连接。为了获得对该过程的全面理解，应对影响粘结强度的主要因素进行数值模拟和实验。这些包括聚合物挤出的参数以及型材表面处的几何孔结构的受控修改，其可以通过挤出的铝合金的发泡行为来调节。最初应使用模拟工具开发合适的孔径和孔分布，然后通过修改铝合金成分和研究挤压工艺变量来实验实现。应通过使用X射线显微镜进行计算机断层扫描，测量实际孔隙结构，验证数值模型。还将使用金相分析和机械测试对功能性混合部件的性能进行评价。

The main objective of the proposed project is the production of hybrid functional components consisting of extruded aluminum profiles that are partly customized by additively manufactured polymers. In this context, the successful creation of a high-quality bond between the different material classes of metals and polymers remains a critical challenge. Hence, a new process approach shall be developed within this proposal, which will enable local foaming of the extruded profile’s surface. The open-porous structure in the peripheral region of the aluminum profile will then provide indentations and undercuts to establish a strong connection between the polymer component and the metal surface by form-closure. In order to gain comprehensive understanding of the process, the main factors influencing the bond strength shall be modeled numerically and experimentally. These include the parameters of polymer extrusion as well as the controlled modification of the geometrical pore structure at the surface of the profile, which can be adjusted by the foaming behavior of the extruded aluminum alloy. Suitable pore sizes and pore distributions shall be developed using simulation tools initially, which will then be realized experimentally by modifications of the composition of the aluminum alloy and an investigation of the process variables of extrusion. The numerical models shall be validated by measurements of the actual pore structures using computed tomography scans with an x-ray microscope. The properties of the functional hybrid components will also be evaluated using metallographic analyses as well as mechanical tests.