添加铌和钼对Nimonic 80A合金激光硼化表面显微组织和磨损行为的影响

来源期刊：中国有色金属学报(英文版)2019年第2期

论文作者：N. MAKUCH P. DZIARSKI M. KULKA A. PIASECKI M. TULINSKI R. MAJCHROWSKI

文章页码：322 - 337

关键词：激光合金化；表面形貌；磨损测试；表面分析；磨损机制；镍基合金

Key words：laser alloying; surface topography; wear testing; surface analysis; wear mechanism; nickel alloy

摘    要：在Nimonic 80A合金表面用激光合金法技术制备较厚的表层。 激光表面改性前在材料表面预涂覆3种浆料：非晶硼、非晶硼与钼和非晶硼与铌。详细研究激光处理后表层的显微组织、硬度和耐磨性能。重熔区不同类型硼化物的形成与浆料成分有关，其硬度增加，可达HV 1000左右。通过计算样品和对磨件的质量磨损强度因子I_mw和相对质量损失来评价样品的耐磨性。采用三维干涉显微镜、扫描电镜和电子能谱仪表征摩擦副的磨损行为。与未处理的Nimonic 80A合金相比，激光处理后的合金其耐磨性明显提高。含硼和铌的Nimonic 80A 合金激光合金化后的表面具有最低的质量损失强度因子(I_mw=1.234 mg/(cm²·h))。激光合金化表层的沟槽清晰可见，其磨损机制为磨粒磨损。经激光处理后含硼和铌合金表面的能谱分析图谱中有氧存在，表现出额外的氧化磨损机制。

Abstract: Laser alloying was used for production of thick layers on surface of Nimonic 80A-alloy. For laser surface modification, three types of pre-coated pastes were applied: with amorphous boron, with amorphous boron and molybdenum as well as with amorphous boron and niobium. The microstructure, hardness and wear resistance of produced layers were studied in details. The presence of different types of borides in re-melted zone depended on the paste composition and caused an increase in hardness up to about HV 1000. The wear resistance was evaluated by calculation of mass wear intensity factor I_mw and relative mass loss of specimen and counter-specimen. The wear behavior of the tested frictional pairs was determined by 3D interference microscopy, scanning electron microscopy equipped with EDS microanalyzer. The significant increase in abrasive wear resistance was observed in comparison to untreated Nimonic 80A-alloy. The lowest mass loss intensity factor was characteristic of laser-alloyed Nimonic 80A-alloy with boron and niobium (I_mw=1.234 mg/(cm²·h)). Laser alloyed-layers indicated abrasive wear mechanism with clearly visible grooves. Laser alloying with boron and niobium resulted in the additional oxidative wear mechanism. In this case, EDS patterns revealed presence of oxygen on the worn surface of specimen.