Co800基激光熔覆/重熔增强多物相复合层组织及耐磨性能

Microstructure and Wear Resistance of Co800 Based Clad/Re-melt Multi-phase Composite Layer

目的增强钛合金表面耐磨损性能。方法采用激光熔覆与激光重熔技术在TC4钛合金表面制备Co800–Si_(3)N_(4)–YPSZ(Y_(2)O_(3)部分稳定ZrO_(2))与Co800–Si_(3)N_(4)–YPSZ–MGOSs(单层氧化石墨烯薄片)复合层,并对熔覆层及重熔层微观组织结构、元素分布及耐磨损性能进行分析。结果细晶强化作用改善了Co800–Si_(3)N_(4)–YPSZ–MGOSs熔覆层的耐磨性。激光重熔后,在熔池快速冷却过程中产生了非晶–纳米晶相,促进了多物相重熔层形成。MGOSs受热分解释放了C,在熔池中原位生成了Ti(CN)。结论含有Ti5Si_(3)、TiN及TiC等多种硬质增强相的Co800–Si_(3)N_(4)–YPSZ–MGOSs熔覆层的摩擦因数较TC4的摩擦因数降低,其磨损体积约为TC4磨损体积的1/7。

The work aims to strengthen the wear resistance of titanium alloy surface.Co800-Si_(3)N_(4)-YPSZ(yttria partially stabilized zirconia)and Co800-Si_(3)N_(4)-YPSZ-MGOSs(monolayer graphene oxide sheet)composite layers were prepared on the TC4 titanium alloy by laser cladding/re-melting technology and the microstructure,element distribution and wear resistance of the clad/re-melt layers were analyzed.The wear resistance of Co800-Si_(3)N_(4)-YPSZ-MGOSs clad layer was enhanced by the fine grain strengthening.The amorphous and nanocrystalline phases were produced under an action of the rapid cooling rate of a laser induced pool after laser re-melting process,promoting the formation of multi-phase re-melt layer.MGOSs released C due to thermal decomposition in the laser induced pool,forming Ti(CN)by in-situ reaction.The friction coefficient of Co800-Si_(3)N_(4)-YPSZ-MGOSs clad layer is lower than that of TC4 due to the formation of the reinforcement phases such as Ti5Si_(3),TiN,TiC,etc.,so the wear volume loss is about 1/7 of that of TC4.