Multi-material additive manufacturing, as an additive manufacturing technique with the ability to simultaneously print multiple materials, is widely used in generating composites with multi-colors, complex multi-material structures, and materials with gradient properties. It also becomes a powerful tool in the study of structure-property relationship in composites, mechanical metamaterials, biological and bioinspired materials. However, the material mixing at the printed interfaces leads to unpredictable material properties which will significantly affect the overall performance of the 3D printed materials or parts. In this study, we systematically investigate the tensile properties, including stiffness and strength, of 3D printed multi-material interfaces. The specimens with double and multiple interfaces are designed, fabricated, and tested. The effect of the material jetting process on the topology of the interface and the effect of printing orientation and material thickness on the mechanical properties are evaluated experimentally. A material mixing model based on hyperbolic tangent function is proposed to quantitatively describe the material property distribution at the interface. The findings reported here provide a deep understanding of the mechanical properties of 3D printed multi-material interfaces, and therefore provide guidelines for the design and fabrication of 3D printed multi-material architectures and materials with desired properties.

多材料增材制造作为一种能够同时打印多种材料的增材制造技术，被广泛用于生成具有多种颜色，复杂的多材料结构和具有渐变特性的材料的复合材料。它也成为研究复合材料，机械超材料，生物和生物启发材料的结构-属性关系的有力工具。但是，打印界面处的材料混合会导致不可预测的材料性能，这将显着影响3D打印材料或零件的整体性能。在这项研究中，我们系统地研究了3D打印多材料界面的拉伸特性，包括刚度和强度。具有双重和多重界面的标本被设计，制造和测试。实验评估了材料喷射过程对界面拓扑的影响以及印刷方向和材料厚度对机械性能的影响。提出了一种基于双曲正切函数的材料混合模型，定量描述了界面处的材料特性分布。此处报告的发现提供了对3D打印多材料界面的机械性能的深刻理解，因此为3D打印多材料架构和具有所需特性的材料的设计和制造提供了指导。提出了一种基于双曲正切函数的材料混合模型，定量描述了界面处的材料特性分布。此处报告的发现提供了对3D打印多材料界面的机械性能的深刻理解，因此为3D打印多材料架构和具有所需特性的材料的设计和制造提供了指导。提出了一种基于双曲正切函数的材料混合模型，定量描述了界面处的材料特性分布。此处报告的发现提供了对3D打印多材料界面的机械性能的深刻理解，因此为3D打印多材料架构和具有所需特性的材料的设计和制造提供了指导。