具有点阵结构的多孔Ni-Fe合金电沉积制备

Lattice-Structured Porous Ni-Fe Alloy Prepared by Electrodeposition

摘要:

采用电沉积耦合增材制造技术制备了具有点阵结构且孔隙率高（95%~98%）的多孔Ni-Fe合金。设计了四面体型和简单立方型2种点阵结构模型，发现减小杆元长度或增大杆元直径和杆元与水平方向夹角可显著提高点阵结构的比表面积。分析了电沉积参数对多孔Ni-Fe合金宏观形貌及结构特征的影响，确立最佳电沉积工艺条件是：阴极电流密度为2~3 A·dm^-2、沉积温度为50~60 ℃、镀液pH值为3、沉积时间为1 h。在此优化条件下制备了四面体型与简单立方型多孔Ni-Fe合金，经单向准静态压缩实验测试，四面体型多孔Ni-Fe合金的屈服强度达到22.91 MPa，比简单立方型提高35.8%。有限元模拟结果表明两种点阵结构在压缩载荷下应力均集中于节点区域，应力集中是导致局部变形与断裂的主要原因。

Abstract:

The lattice-structured porous Ni-Fe alloys with high porosity (95%?98%) were prepared by electrodeposition coupled with additive manufacturing technique. Two types of lattice-structured models were designed, namely tetrahedral structure and simple cubic. It is found that reducing the strut length or increasing the strut diameter and the inclination angle of struts relative to the horizontal direction significantly enhances the specific surface area of the lattice structures. The influence of electrodeposition parameters on the macroscopic morphology and structural characteristics of the porous Ni-Fe alloys was analyzed. The optimal electrodeposition conditions are determined as follows: cathode current density of 2?3 A·dm^-2, deposition temperature of 50?60 ℃, electrolyte pH of 3, and deposition time of 1 h. Under such condition, both tetrahedral and simple cubic porous Ni-Fe alloys were prepared. The uniaxial quasi-static compression tests demonstrate that the yield strength of the tetrahedral porous Ni-Fe alloy reaches 22.91 MPa, which is 35.8% higher than that of the simple cubic structure. Finite element simulation results indicate that the stress under compressive loading is concentrated in the nodal regions of the alloys with both two lattice structures. The stress concentration is the main cause for the local deformation and fracture.