Functionally graded material (FGM) can tailor properties of components such as wear resistance, corrosion resistance, and functionality to enhance the overall performance. The selective laser melting (SLM) additive manufacturing highlights the capability in manufacturing FGMs with a high geometrical complexity and manufacture flexibility. In this work, the 316L/CuSn10/18Ni300/CoCr four-type materials FGMs were fabricated using SLM. The microstructure and properties of the FGMs were investigated to reveal the effects of SLM processing parameters on the defects. A large number of microcracks were found at the 316L/CuSn10 interface, which initiated from the fusion boundary of 316L region and extended along the building direction. The elastic modulus and nano-hardness in the 18Ni300/CoCr fusion zone decreased significantly, less than those in the 18Ni300 region or the CoCr region. The iron and copper elements were well diffused in the 316L/CuSn10 fusion zone, while elements in the CuSn10/18Ni300 and the 18Ni300/CoCr fusion zones showed significantly gradient transitions. Compared with other regions, the width of the CuSn10/18Ni300 interface and the CuSn10 region expand significantly. The mechanisms of materials fusion and crack generation at the 316L/CuSn10 interface were discussed. In addition, FGM structures without macro-crack were built by only altering the deposition subsequence of 316L and CuSn10, which provides a guide for the additive manufacturing of FGM structures.

功能梯度材料（FGM）可以调整组件的属性，例如耐磨性，耐腐蚀性和功能性，以增强整体性能。选择性激光熔融（SLM）增材制造技术突出了制造具有高几何复杂度和制造灵活性的FGM的能力。在这项工作中，使用SLM制造了316L / CuSn10 / 18Ni300 / CoCr四型材料FGM。研究了FGM的微观结构和性能，以揭示SLM加工参数对缺陷的影响。在316L / CuSn10界面处发现了大量的微裂纹，它们是从316L区域的融合边界开始并沿构建方向延伸的。18Ni300 / CoCr熔合区的弹性模量和纳米硬度明显降低，小于18Ni300区域或CoCr区域中的那些。铁元素和铜元素在316L / CuSn10融合区中的扩散良好，而CuSn10 / 18Ni300和18Ni300 / CoCr融合区中的元素则表现出明显的梯度转变。与其他区域相比，CuSn10 / 18Ni300界面和CuSn10区域的宽度显着扩大。讨论了在316L / CuSn10界面处材料熔合和裂纹产生的机理。此外，仅通过改变316L和CuSn10的沉积顺序就可以构建不具有宏观裂纹的FGM结构，这为FGM结构的增材制造提供了指导。CuSn10 / 18Ni300和18Ni300 / CoCr熔合区中的元素显示出明显的梯度转变。与其他区域相比，CuSn10 / 18Ni300界面和CuSn10区域的宽度显着扩大。讨论了在316L / CuSn10界面处材料熔合和裂纹产生的机理。此外，仅通过改变316L和CuSn10的沉积顺序就可以构建不具有宏观裂纹的FGM结构，这为FGM结构的增材制造提供了指导。CuSn10 / 18Ni300和18Ni300 / CoCr熔合区中的元素显示出明显的梯度转变。与其他区域相比，CuSn10 / 18Ni300界面和CuSn10区域的宽度显着扩大。讨论了在316L / CuSn10界面处材料熔合和裂纹产生的机理。此外，仅通过改变316L和CuSn10的沉积顺序就可以构建不具有宏观裂纹的FGM结构，这为FGM结构的增材制造提供了指导。