激光熔覆制备原位自生TiC颗粒强化Ni基合金复合涂层的研究

Research on in-situ formation of tiC particles reinforced nickel base alloy coating Produced by laser cladding

为了在碳钢表面获得耐磨、耐蚀、抗热疲劳等综合性能优良的TiC颗粒强化Ni基合金复合涂层 ,利用3kW连续波快速轴流CO2 激光器进行了一系列的激光表面熔覆实验研究 ,光斑直径 3 5mm ,扫描速度 3 10mm/s,送粉速率 3 2 6 g/min。实验结果表明 :利用送粉式激光表面熔覆技术 ,可以在碳钢表面直接原位合成TiC颗粒增强的Ni基合金复合涂层 ,涂层与基体呈良好的冶金结合 ,涂层宏观质量完好 ,无裂纹 ,但有少量的气孔。涂层组织由γ 奥氏体枝晶、CrB、TiB2 、M2 3 C6和TiC组成。经激光表面重熔后 ,涂层显微硬度达HV0 2 110 0 ,是基材显微硬度的 4

In order to improve resistance to thermal fatigue, wear and corrosion resistance of carbon steel, the laser cladding experiments were conducted on a 3kW continuous wave CO2 laser. The diameter of the laser beam is 3-5mm, the scanning velocity is 3-10mm/s, and the powder feeding rate is 3.26g/min. The experimental results showed that a composites coating with TiC particles of various shapes and sizes embedded in nickel based alloy can be in-situ synthesized from the mixture of nickel based alloy powder, graphite enwrapped nickel and titanium powders by powder feeding laser cladding. An excellent bonding between the coating and the carbon steel substrate was ensured by the strong metallurgical interface. The coating is uniform, continuous and free from cracks, however there existed some pores in coatings. The microstructure of the coating is mainly composed of γ-Ni dendrite, a small amount of CrB, TiB2, M23C6 and dispersed TiC particles. The average microhardness of the coating is about HV0.21100 after laser surface remelting, 4.5 times larger than that of the steel substrate.