Ti-6Al-4V合金表面激光熔覆TiAlSi+xB4C涂层的组织及耐磨性

利用激光熔覆在Ti-6Al-4V合金表面制备了TiAlSi+xB₄C涂层,分析比较不同B₄C含量对于涂层显微组织、显微硬度和耐磨性能的影响。结果表明:B₄C含量不同,涂层中的物相种类差别不大;涂层的微观形貌由颗粒状晶、层状晶、胞状晶和短棒状晶组成;不同B₄C含量涂层的显微硬度分布趋势大致相同,与基材相比均有明显的提高,随着B₄C含量的增高,整体上涂层显微硬度逐渐增大,当B₄C的含量为8%时,涂层的显微硬度最高,达到1216 HV0.1,约为基体的4.2倍;而当B₄C含量过高时,涂层硬度降低,且涂层中出现微裂纹。通过磨损试验表明,不同B₄C含量的涂层耐磨损性能均明显的优于Ti-6Al-4V合金基体,含8%B₄C的涂层磨损量最小。熔覆不同含量B₄C的涂层明显改善了基体Ti-6Al-4V合金的表面性能。

Microstructure and wear resistance of laser clad TiAlSi+xB4 C coatings on Ti-6 Al-4V alloy

Ti Al Si+x B₄C coatings were prepared on the surface of Ti-6Al-4V alloy by laser cladding,and the effects of different B₄C content on microstructure,microhardness and wear resistance of the coatings were analyzed.The results show that different content of B₄C makes little difference in the phase type of the coating.The micro morphology of the clad coating is composed of granular crystals,layered crystals,cell crystals and short rod crystals.The microhardness distribution of the coatings with different content of B₄C is about the same,but is obviously improved compared with the substrate.With the increase of B₄C content,the microhardness tends to increase on the whole,when the content of B₄C is 8%,the microhardness reaches the highest,that is 1216 HV0.1,about 4.2 times of the substrate.However,when the B₄C content is much higher,the hardness decreases and microcracks appear.Wear experiments show that the wear resistance of the coatings with different content of B₄C is significantly better than that of Ti-6Al-4V alloy substrate,and the coating with 8%B₄C has the minimum wear loss.The results show that the cladding of coating with different content of B₄C obviously improves the surface properties of the Ti-6Al-4V alloy substrate.