CAJ | 학술논문

采用HL-5000型横流CO 2激光器在氩气保护情况下对预置石墨和硅混合粉末的β型Ti-7.5Nb-4Mo-2Sn钛合金进行激光表面合金化处理，在合金表面原位生成碳、硅和钛的化合物改性层，并对其激光表面合金化改性层的显微组织和耐磨性能进行研究。结果表明，在激光功率1200 W、激光扫描速度6 mm/s、激光束斑直径5 mm条件下，得到表面平整、细密、无裂纹且与基体形成良好冶金结合的激光表面合金化改性层；改性层外表面主要由细小的TiC颗粒和等轴状Ti5Si3C1-x组成，而靠近基体的内表面层则由TiC枝晶相和共晶组织(Ti3SiC2+β-Ti)组成；改性层外表面硬度可达1262HV0.2，摩擦因数约为0.649，而基体的硬度约为225HV0.2，摩擦因数约为1.039；与基体合金相比，基体的表面合金化改性层表现出良好的耐磨性能。
채용HL-5000형횡류CO 2격광기재아기보호정황하대예치석묵화규혼합분말적β형Ti-7.5Nb-4Mo-2Sn태합금진행격광표면합금화처리，재합금표면원위생성탄、규화태적화합물개성층，병대기격광표면합금화개성층적현미조직화내마성능진행연구。결과표명，재격광공솔1200 W、격광소묘속도6 mm/s、격광속반직경5 mm조건하，득도표면평정、세밀、무렬문차여기체형성량호야금결합적격광표면합금화개성층；개성층외표면주요유세소적TiC과립화등축상Ti5Si3C1-x조성，이고근기체적내표면층칙유TiC지정상화공정조직(Ti3SiC2+β-Ti)조성；개성층외표면경도가체1262HV0.2，마찰인수약위0.649，이기체적경도약위225HV0.2，마찰인수약위1.039；여기체합금상비，기체적표면합금화개성층표현출량호적내마성능。
A wear resistance in-situ modified coating was fabricated by 5.0 kW continuous wave CO2 laser alloying technique with silicon and graphite mixed powders on the substrate of aβ-type Ti-7.5Nb-4Mo-2Sn under the protection atmosphere of Ar, and its microstructure and wear properties were investigated. The results show that, under the conditions of laser power of 1200 W, scanning rate of 6 mm/s and beam diameter of 5 mm, a defect-free coating with multi-phases was obtained. The coating consists of two layers. The microstructure of the top layer mainly contains fine TiC particles and equiaxed Ti 5 Si 3 C 1-x phase, while, in the layer close to the substrate, dendritic TiC phase and eutectic phases of Ti3SiC2+β-Ti form. The hardness of the top layer is up to 1262HV0.2,which is much higher than that of the Ti-7.5Nb-4Mo-2Sn substrate (about 225HV 0.2 ). The friction coefficient of the coating is about 0.649, which is much lower than that of the substrate (of about 1.039). The coating exhibits good wear-resisting performance in comparison with Ti-7.5Nb-4Mo-2Sn substrate.