选区激光熔化制备316L不锈钢点阵结构的力学性能研究

Mechanical Properties of 316L Stainless Steel Lattice Structure Prepared by Selective Laser Melting

利用选区激光熔化技术制备了3种类型的316L不锈钢点阵结构试样。进行了准静态单轴压缩试验,结果显示,与实体金属结构相比,点阵结构的弹性模量从180 GPa降低至2 GPa以下。进一步地研究发现,孔隙率是影响点阵结构刚度的主要因素之一,并得到了相应的数值关系。在保证整体尺寸和孔隙率不变的情况下,点阵的大小和数量的改变对点阵结构刚度和屈服强度的影响较小。然后建立了有限元模型分析全尺寸点阵结构的宏观变形和应力分布以及单点阵的微观应力、应变的变化规律。利用超景深显微系统检测了试样的打印精度,发现在垂直于打印方向上测量的杆径值均大于平行于打印方向上测量的杆径值。最后根据工业用计算机断层成像系统检测结果,得到了点阵结构的变形机制。

Laser selective melting technology was used to prepare three types of 316L stainless steel lattice structure samples with different porosities and pore sizes.The samples were subjected to quasistatic uniaxial compression tests.The test results showed that,compared with the solid metal structure,the elastic modulus of the lattice structure decreased from 180 GPa to 2 GPa.Furthermore,porosity was found to be the main factor affecting the lattice structure stiffness,and the corresponding numerical relationship was obtained.Under the condition of keeping the overall size and porosity unchanged,the change of lattice size and number was observed to have little effect on the stiffness and yield strength of lattice structure.The finite element model was applied to analyze the macroscopic deformation and stress distribution of the fullsize lattice structure and the variation of the micro stress and strain of the single lattice.The printing accuracy of the sample was tested using an industrial CT system.The test show that the diameter of the rod measured perpendicular to the printing direction is greater than that measured parallel to the printing direction.According to the test results of the industrial CT system,the deformation mechanism of lattice structure is obtained.