实时混粉梯度材料SLM成型系统构建与实验

为了在成型过程中，方便地在零件上按需获得梯度材料成分，采用了集成同步送粉碰撞混合、锥形聚集混合、气流混合等多重混粉动作的实时混粉方法，研制成梯度材料激光选区熔化增材制造系统，并展开了梯度材料成型实验验证，结合试样照片、显微图像及能谱仪检测，分析了成型效果。结果表明，系统可自由按需在水平及垂直方向添加成分渐变材料，可方便获得具有复杂外形结构的梯度材料零件；成型件梯度材料区域微区成分分析显示，各微区内元素平均质量分数离散程度小，成型过程中每层平均混粉时间10s~15s时，各微区主要元素变异系数不超0.59，达到了较好的混合均匀性。该研究为自由制造梯度材料零件提供了新途径。

System construction and experiment for SLM of gradient materials based on real-time powder mixing methods

In order to obtain the gradient material composition of parts easily in the part forming process, a selective laser melting additive manufacturing system for gradient materials was developed by using the real-time powder mixing method which integrates multiple powder mixing actions such as impact mixing after synchronous discharge powders, converging mixing through a conical cavity, and air flow mixing. With this system, the experimental verification of gradient material forming was carried out, and the forming effect was analyzed combined with the sample photos, microscopic images, and energy spectrometer detection. The result shows that the gradient materials can be freely added in the horizontal and vertical directions to produce gradient material parts with complex shape and structure in the system. The micro areas composition analysis of the gradient material zones of the gradient material part shows that the dispersion degree of the average mass content of elements in each micro zone is small. The variability coefficient of the main elements in each micro zone is not more than 0.59 when the average powder mixing time of each layer is 10s~15s during selective laser melting process, achieving good mixing uniformity.This research provides a new way for free manufacturing of gradient material parts.