Abstract Functionally graded materials (FGMs) with spatially varying material properties in 3D space are highly desired for a wide range of applications. Although FGMs are ubiquitous in biological materials, the fabrication of FGMs with continuous non-linear spatial variation of material properties remains a great challenge. Here we present a self-developed extrusion-based additive manufacturing system capable of fabricating FGMs with sophisticated material property distributions. The workflow involves property function modeling, gray-scale representation and control codes generation, digital material feeding and active multi-material mixing. The effectiveness of the technology is demonstrated by the successful printing of a diverse range of objects with complex spatial variations in color and Al2O3 concentration. In addition, by controlling the dynamic change of the different components during reactive 3D printing process, we can fabricate polyurethane (PU) objects with various gradient patterns in material mechanical properties. The results of the cantilever bending test and simulation show that the material gradient can effectively relieve the stress concentration. The proposed gradient 3D printing system opens a new avenue for manufacturing FGMs with exquisite material property distributions thus far only accessible by biological materials grown in nature.

中文翻译：

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具有空间非线性变化特性的材料的 3D 打印

摘要 功能梯度材料 (FGMs) 在 3D 空间中具有空间变化的材料特性，因此非常需要广泛的应用。尽管 FGMs 在生物材料中无处不在，但材料特性连续非线性空间变化的 FGMs 的制造仍然是一个巨大的挑战。在这里，我们提出了一种自主开发的基于挤压的增材制造系统，能够制造具有复杂材料特性分布的 FGM。工作流程包括属性函数建模、灰度表示和控制代码生成、数字材料进料和主动多材料混合。该技术的有效性通过成功打印颜色和 Al2O3 浓度具有复杂空间变化的各种物体来证明。此外，通过控制反应性 3D 打印过程中不同组分的动态变化，我们可以制造出具有各种材料力学性能梯度图案的聚氨酯 (PU) 物体。悬臂弯曲试验和仿真结果表明，材料梯度可以有效缓解应力集中。所提出的梯度 3D 打印系统为制造具有精细材料特性分布的 FGM 开辟了一条新途径，迄今为止只能通过自然界中生长的生物材料获得。悬臂弯曲试验和仿真结果表明，材料梯度可以有效缓解应力集中。所提出的梯度 3D 打印系统为制造具有精细材料特性分布的 FGM 开辟了一条新途径，迄今为止只能通过自然界中生长的生物材料获得。悬臂弯曲试验和仿真结果表明，材料梯度可以有效缓解应力集中。所提出的梯度 3D 打印系统为制造具有精细材料特性分布的 FGM 开辟了一条新途径，迄今为止只能通过自然界中生长的生物材料获得。