Lv Xiangzhe, Zhan Zaiji, Cao Haiyao
State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China.
Micromachines (Basel). 2022 Jan 28;13(2):212. doi: 10.3390/mi13020212.
Laser additive manufacturing is an advanced material preparation technology, which has been widely used to prepare various materials, such as polymers, metals, ceramics and composites. Zirconium diboride (ZrB) reinforced copper composite material was fabricated using laser direct energy deposition technology. The microstructure and phase composition of the composite material were analyzed, and the influence of laser energy density on the microstructure and mechanical properties of composite materials was discussed. The results showed that the needle-like ZrB ceramic reinforcement was successfully synthesized via an in-situ synthesis reaction. The composites were mainly composed of needle-like ZrB, Ni dendrites and a Cu matrix. The morphological changes of Ni dendrites could be observed at the interface inside the composite material: cellular crystals → large-sized columnar dendrites → small-sized dendrites (along the solidification direction). The continuous Ni dendritic network connected the ZrB reinforcements together, which significantly improved the mechanical properties of the composite material. At a laser energy density of 0.20 kJ/mm, the average microhardness of the composite material reached 294 HV and the highest tensile strength was 535 MPa. With the laser energy density increased to 0.27 kJ/mm, the hardness and tensile strength decreased and the elongation of the Cu composites increased due to an increase in the size of the ZrB and a decrease in the continuity of the Ni dendritic.
激光增材制造是一种先进的材料制备技术，已被广泛用于制备各种材料，如聚合物、金属、陶瓷和复合材料。采用激光直接能量沉积技术制备了二硼化锆（ZrB）增强铜复合材料。分析了复合材料的微观结构和相组成，并讨论了激光能量密度对复合材料微观结构和力学性能的影响。结果表明，通过原位合成反应成功合成了针状ZrB陶瓷增强体。复合材料主要由针状ZrB、Ni枝晶和Cu基体组成。在复合材料内部界面处可观察到Ni枝晶的形态变化：胞状晶→大尺寸柱状枝晶→小尺寸枝晶（沿凝固方向）。连续的Ni枝晶网络将ZrB增强体连接在一起，显著提高了复合材料的力学性能。在激光能量密度为0.20 kJ/mm时，复合材料的平均显微硬度达到294 HV，最高抗拉强度为535 MPa。随着激光能量密度增加到0.27 kJ/mm，由于ZrB尺寸增大和Ni枝晶连续性降低，Cu复合材料的硬度和抗拉强度降低，伸长率增加。
