激光重熔参数对镍基纳米TiN复合电沉积镀层性能的影响

Effect of Laser Remelting Parameters on Properties of Nickel-based Nano TiN Composite Deposition Coatings

目的在Ni Cr20Ti Al基体材料上进行镍基纳米Ti N电沉积复合镀后再开展激光重熔工艺,研究激光重熔参数对镀层表面质量、结合力及硬度的影响。方法采用正交实验,研究不同激光重熔参数(扫描速率、搭接量、离焦量等)对重熔镀层的影响,采用显微硬度计、扫描电镜和划痕仪进行硬度、表面形貌和结合力检测,以得到较优工艺参数。结果通过控制重熔参数对镀层表面能量和表面形貌的影响,以降低表面性能差异,以得到了激光重熔较佳工艺参数为:电流115 A,脉宽为8 ms,频率为10 Hz,离焦量15 mm,扫描速度230 mm/min,使获得的镀层表面形貌比较平整,结合力提高到大于60 N,硬度值平均为632HV,并且硬度分布均匀。结论激光重熔工艺可消除纳米复合电沉积过程中产生的间隙,纳米复合镀层致密均匀,镀层与基体之间产生良好的冶金结合,镀层表面硬度分布均匀,力学性能趋近一致。

Objective Nickel-based nano Ti N composite deposition coatings were remelted by laser process. The effects of laser remelting parameters on the surface quality,binding force and hardness of the coatings were researched. Methods Orthogonal experiments were used to study the effects of different laser remelting parameters（ scan rate,amout of overlap,defocus amount,etc）on the remelted coating,and the hardness,surface morphology and binding force were tested by using microhardness meter,SEM and scratch tester,in order to obtain optimal process parameters. Results By controlling the effects of remelting parameters on the coating surface energy and surface morphology in order to reduce the differences in surface properties,preferable laser remelting process parameters were obtained： electric current 115 A,pulse width 8 ms,frequency 10 Hz,defocus amount 15 mm,and scanning speed 230 mm / min. Under this condition,smooth surface morphology was obtained,with the binding force improved to 60 N,the average hardness value reaching 632 HV,and the hardness distribution was uniform. Conclusion Laser remelting process could eliminate the gap produced by nano composite deposition,and the nano composite coating became compact and uniform. A good metallurgical bond could be formed between the coating and the substrate,the hardness distribution was uniform on the coating surface and the mechanical properties tended to be consistent.