CNTs的添加对激光粉末床熔融纯铜的微观结构和力学及导电导热性能的影响

Effects of the addition of CNTs on microstructure, mechanics and thermal conductivity of pure copper in laser powder bed melting

摘要:

激光粉末床熔合(L-PBF)工艺制造铜通常表现出较差的强度-塑性配合,添加增强相通常是改善这种配合的有效方法。然而,对Cu复合材料的研究相对有限。为了探究增强相对Cu的影响,我们以Cu-CNTs混合粉末为基体,采用L-PBF技术制备Cu-CNTs复合材料。研究了其成形性能、微观结构、力学性能、导电性能和热性能。所得复合材料具有较高的的相对密度。CNTs的加入导致了熔池边缘等轴晶粒和中心柱状晶粒的不均匀组织。与纯铜相比,复合材料的整体力学性能得到改善(抗拉强度提高52.8%,伸长率提高115.9%),电性能和热性能也得到提高(导热系数提高10.8%,电导率提高12.7%)。结果表明,CNTs的加入可以提高铜的抗拉强度和伸长率,以及铜的电学和热学性能。因此,这种材料为设计更高效的散热器结构提供了有效途径。

Abstract:

The laser powder bed fusion (L-PBF) process for manufacturing copper typically exhibits poor strength-ductility coordination； the addition of enhancers is usually an effective way to improve it. However, there is relatively limited research on Cu composites. To explore the impact of enhancements on Cu, we used a Cu-CNTs mixed powder as the base and applied the L-PBF technology to produce a Cu-CNTs composite. We studied its forming performance, microstructure, and mechanical properties, as well as its conductive and thermal properties. The resulting composite has a high relative density of consolidated Cu-CNTs material. The addition of CNTs results in non-uniform microstructure with equiaxed grains at the edges of the melt pool and columnar grains at the center. Compared to pure copper, the overall mechanical properties of the composite are improved (tensile strength increased by 52.8%, elongation increased by 115.9%), and the electrical and thermal properties are also enhanced (thermal conductivity increased by 10.8%, electrical conductivity increased by 12.7%). The results indicate that the addition of CNTs can increase the tensile strength and elongation, as well as the electrical and thermal properties of copper. Therefore, this material provides an efficient pathway for designing more efficient heat sink structures.