3D打印模拟月壤道路材料制备与性能研究

为了制备可用于3D打印的模拟月壤道路材料,对月球原位资源利用进行初期探索,以水胶比0.28~0.32的BH-1模拟月壤地聚合物浆体为打印墨水,采用动态剪切流变试验测试了打印温度在40℃~80℃下浆体的流动曲线,通过宾汉姆模型拟合得到了屈服应力和塑性黏度2个流变参数,以上行流动曲线和下行流动曲线计算得到的触变环面积表征材料的剪切破坏特性。利用3D打印机的送料机构研究了浆体的可挤出性和施工时限,并确定了二者与流变参数的关系。提出了一种利用三维轮廓扫描仪提取3D打印试件表面三维点云,进而获取材料整体变形和表面纹理的测试方法,以对材料的可建造性进行定量评价。最后研究了不同填充率对3D打印试件力学性能和打印效率的影响。结果表明:BH-1模拟月壤地聚合物浆体呈剪切变稀特性,屈服应力和塑性黏度随水胶比增大而减小,随静置时间延长而增大,且打印温度越高,增长速度越快;能够完成挤出的材料屈服应力上限值为1 090 Pa,塑性黏度为11.5 Pa·s;水胶比越大,打印温度越低,对应的材料可挤出性越强,施工时限越长;提升打印温度有利于提升材料的可建造性,在所有试验组中,水胶比为0.32,打印温度为80℃时可以在满足可挤出性和较长施工时限的前提下,有效控制打印试件的变形;降低填充率会导致材料力学性能下降,但是能够提升3D打印速度,节约材料。

Preparation and Performance Evaluation on 3D Printed Road Material Based on Lunar Soil Simulant

In order to prepare road materials with lunar soil simulant that can be used for 3D printing and to initially explore the technology of in-situ lunar resource utilization,geopolymer slurry based on BH-1 lunar soil simulant with a water-ash ratio of 0.28-0.32 was used as the printing ink,and the flow curves of the slurry were tested at the printing temperature of 40℃-80℃ using dynamic shear rheological tests.Two rheological parameters,yield stress and plastic viscosity,were obtained by fitting the Bingham model.The upward flow curve and downward flow curve were calculated,obtaining the thixotropic ring area to characterize the shear damage properties of the material.The of the slurry were investigated using the feeding mechanism of the 3D printing machine.The relationship between the two workability and the rheological parameters was determined.A test method for extracting 3D point clouds on the surface of 3D printed specimens using a 3D contour scanner,and then obtaining the overall material deformation and surface texture,was proposed to quantitatively evaluate the buildability of the material.Finally,the effects of different filling rates on the mechanical properties and printing efficiency of 3D printed specimens were investigated.The results show that the BH-1 geopolymer slurry is of shear thinning characteristics.The yield stress and plastic viscosity coefficient decrease with increasing water-ash ratio,increase with resting time.And the higher the printing temperature,the faster the lifting speed.The upper limit of yield stress is 1 090 Pa and the plastic viscosity is 11.5 Pa·s for successful extrusion.The larger the water-ash ratio,the lower the printing temperature,the stronger the extrudability of the materials and the longer the construction time.Raising the printing temperature is beneficial to enhance the buildability of the material.In all test groups,a water-ash ratio of 0.32 and a printing temperature of 80℃ can effectively control the deformation of the printed specimens while satisfying the extrudability and a longer open time limit.Reducing the filling rate leads to a decrease in the mechanical properties of the material but can enhance the 3D printing speed and save material.