Abstract

In situ ceramic phase reinforced Ti-based composite coatings were successfully fabricated on Ti-6Al-4V alloys by laser cladding using Ti + Al + Si mixed powders with different NbC contents (0, 5, 10, 15 wt.%). The effects of different NbC content on the microstructural evolution, hardness, and wear behaviors of the Ti-based composite coatings were studied. The results showed that the phase in the cladding layer was mainly consisted of Ti₃Al, TiAl, and Ti₅Si₃ before NbC was added. After NbC was added, the TiC and Ti₃AlC₂ ceramic reinforcement phase was in suit synthesized. In addition, (Ti, Nb)C were also found. The in situ formed phases were proved beneficial to the improvement of the coating property. With the addition of NbC, the hardness of the coating is apparently increased. When the content of NbC is 15%, the maximum hardness of the coating is 1024 HV_0.2, which is almost three times that of the substrate. The coefficient of friction of the coating without NbC was 0.591. With the addition of NbC, the coefficient of friction of S2, S3, and S4 was significantly decreased to 0.450, 0.388, and 0.375, respectively. Furthermore, the addition of NbC improves the worn surface of the coatings.

中文翻译：

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NbC增强Ti基复合涂层的组织演变和磨损行为

摘要

使用具有不同NbC含量（0、5、10、15 wt。％）的Ti + Al + Si混合粉末，通过激光熔覆成功地在Ti-6Al-4V合金上制备了原位陶瓷相增强Ti基复合涂层。研究了不同NbC含量对Ti基复合涂层微观组织演变，硬度和磨损行为的影响。结果表明，在添加NbC之前，熔覆层中的相主要由Ti ₃ Al，TiAl和Ti ₅ Si _3组成。添加NbC后，TiC和Ti ₃ AlC ₂适合合成陶瓷增强相。另外，还发现了（Ti，Nb）C。事实证明，原位形成的相有利于改善涂层性能。随着NbC的添加，涂层的硬度明显增加。当NbC的含量为15％时，涂层的最大硬度为1024 HV _0.2，几乎是基材的三倍。没有NbC的涂层的摩擦系数为0.591。通过添加NbC，S2，S3和S4的摩擦系数分别显着降低至0.450、0.388和0.375。此外，NbC的添加改善了涂层的磨损表面。