选择性激光熔化(SLM)成形纯钨的微观组织与力学性能研究

目的 研究选择性激光熔化(SLM)技术制备的成形钨的微观组织和力学性能。方法 采用纯钨粉末作为原材料，利用SLM技术制备了高密度的纯钨试样，系统研究其孔隙与裂纹的形成机理。同时，利用光学显微镜、显微维氏硬度计和压缩实验等分析手段，分别沿水平面(x-y)和垂直平面(z-x)对其微观组织与力学性能进行分析，探究SLM成形纯钨的各向异性。结果 成功制备了相对密度为97.79%的高致密纯钨试样，在水平面上，组织主要为呈长条形的柱状晶，在垂直平面上，组织为粗大的胞状晶，断口形貌表现为典型的宏观脆性断裂特征。在水平面上，试样具有更高的抗压强度(1 100 MPa)和显微硬度(427±5)HV。结论 孔隙的形成主要与Marangoni效应有关，而裂纹的产生主要取决于材料本身的特性和SLM工艺参数。组织的各向异性导致2个平面的力学性能有一定差异。

Microstructure and Mechanical Properties of Pure Tungsten Fabricated by Selective Laser Melting (SLM)

The work aims to investigate the microstructure and mechanical properties of tungsten fabricated by the Selective Laser Melting (SLM) technology. Pure tungsten powder was employed as the raw material to fabricate high-density tungsten samples through the Selective Laser Melting (SLM) technology. The formation mechanisms of pores and cracks were systematically studied. Additionally, analysis was carried out with optical microscopy, micro Vickers hardness testing, and compression experiments, from both the horizontal (x-y) and vertical (z-x) planes, to explore the anisotropy of SLM-fabricated tungsten. The experimental outcomes demonstrated the successful fabrication of highly dense pure tungsten samples with a relative density of 97.79%. The microstructure analysis revealed elongated columnar crystals in the horizontal plane, whereas a coarser cellular structure was observed in the vertical plane. The fracture surface exhibited typical macroscopic brittle fracture characteristics. Moreover, in the horizontal plane, the samples exhibited superior compressive strength (1 100 MPa) and microhardness (427±5)HV. Pore formation is primarily affected by the Marangoni effect, while crack generation is mainly governed by material characteristics and SLM process parameters. The anisotropy in microstructure leads to mechanical property variations in the two planes.