Effect of the Scanning speed on microstructural evolution and wear behaviors of laser cladding NiCrBSi composite coatings
Effect of the Scanning speed on microstructural evolution and wear behaviors of laser cladding NiCrBSi composite coatings
复制标题
扫描速度对激光熔覆NiCrBSi复合涂层微观结构演变和磨损行为的影响
DOI：
10.1016/j.optlastec.2015.03.015
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发表时间：
2015-09-01
影响因子：
5
通讯作者：
Qu, C. C.
中科院分区：
文献类型：
--
作者：
Chen, J. L.;Li, J.;Qu, C. C.
采用光纤激光熔覆NiCrBSi合金粉末，在Ti6Al4V基片表面制备了激光熔覆复合涂层。利用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)和能谱仪(EDS)详细研究了扫描速度对涂层稀释率和组织结构的影响。结合显微硬度和断裂韧性的分析，揭示了不同扫描速度下获得的涂层的磨损行为。结果表明，在扫描速度为5 mm/S~15 mm/S范围内，涂层的稀释率相似(约64.23%)。在扫描速度为20 mm/S时，稀释率急剧下降(37.06%)。显微组织观察表明，扫描速度为5~15 mm/S时，块状TiB_2和胞状枝晶TiC颗粒均匀弥散在TiNi-Ti2Ni双相金属间化合物中。当扫描速度进一步提高到20 mm/S时，条状的CrB_2相，原位合成了均匀分散在γ(Ni)基体中的灰色不规则形状的Cr3C2和黑色块状TiC颗粒。扫描速度越高，颗粒越细小。在扫描速度为20 mm/S时，涂层的平均显微硬度(1026.5 Hv0.2)明显高于其他三种涂层的平均硬度(约886.4 Hv0.2)。在扫描速度为20 mm/S时，平均摩擦系数最小，约为0371，且随滑动时间的变化相对稳定。当扫描速度为20 mm/S时，涂层的磨损量最小。磨损表面分析表明，在扫描速度为20 mm/S时制备的涂层具有良好的抗微切削性能和脆性剥离性能。比较而言，以20 mm/S的扫描速度制备的涂层具有良好的综合力学性能。(C)2015爱思唯尔有限公司。保留所有权利。
Laser cladding composite coatings were fabricated on the surface of the Ti6Al4V substrate by fiber laser cladding the NiCrBSi alloy powder. The influences of scanning speed on the dilution rate and microstructure of the coatings were investigated in detail by X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Combined with the analyses of microhardness and fracture toughness, the wear behaviors of the coatings obtained at different scanning speeds were revealed. Results indicated that the dilution rates of the coatings were similar (about 64.23%) with variations in scanning speed ranging from 5 mm/s to 15 mm/s. An abrupt decrease in dilution rate (37.06%) was observed at the scanning speed of 20 mm/s. Microstructural observation showed that the blocky TiB2 and the cellular dendrite TiC particles were uniformly dispersed in the TiNi-Ti2Ni dual-phase intermetallic compound matrix at scanning speeds of 5-15 mm/s. When the scanning speed was further increased to 20 mm/s, the stripe-shaped CrB, gray irregular-shaped Cr3C2 and black blocky TiC particles uniformly dispersed in the gamma(Ni) matrix were synthesized in situ. The particles became finer with the increase in scanning speed. The average microhardness of the coating (1026.5 HV0.2) at the scanning speed of 20 mm/s was enhanced significantly compared with that of the other three coatings (about 886.4 HV0.2). The lowest average friction coefficient (about 0371) was obtained at the scanning speed of 20 mm/s and was relatively stable with the change in sliding time. The lowest wear loss of the coating was also obtained at the scanning speed of 20 mm/s. Analyses of the worn surfaces showed that the coating prepared at the scanning speed of 20 mm/s was in good condition because of its excellent combination of resistance to micro-cutting and brittle debonding. Comparatively speaking, the coating produced at the scanning speed of 20 mm/s possessed excellent comprehensive mechanical properties. (C) 2015 Elsevier Ltd. All rights reserved.