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利用超音速微粒轰击技术(supersonic fine particles bombarding,SFPB)对钛合金TC4进行了表面纳米化处理,并对SFPB处理后的试样进行不同温度2 h退火处理。借助X射线衍射、显微硬度计、透射电子显微镜和差热分析对纳米化及热处理后的试样进行了组织和性能表征,研究钛合金表面纳米化机理及其热稳定性。结果表明:经过SFPB处理后的试样在表层形成了纳米结构层,随着处理时间的延长,变形层厚度不断增加,晶粒尺寸逐步细化,当SFPB处理30 min后晶粒尺寸趋于稳定,在表层形成了晶粒尺寸约为15 nm具有随机取向的纳米等轴晶。纳米化后的试样在750℃退火时,纳米晶未发生明显粗化,因而具有很好的热稳定性。
The surface nanocrystallization of titanium alloy TC4 was carried out by supersonic fine particle bombarding (SFPB), and the samples after SFPB treatment were annealed at different temperatures for 2 h. The microstructure and properties of the samples after nanocrystallization and heat treatment were characterized by means of X-ray diffraction, microhardness tester, transmission electron microscopy and differential thermal analysis, and the mechanism of nanocrystallization and thermal stability of titanium alloy were studied. The results showed that the nanostructured layer was formed on the surface after SFPB treatment. With the increase of treatment time, the thickness of deformed layer increased and the grain size gradually refined. The grain size tended to be stable after SFPB treatment for 30 min , A nano-equiaxed grain with a randomly oriented grain size of about 15 nm was formed on the surface. Nanocrystallization of the sample annealed at 750 ℃, the nanocrystallization did not occur significant coarsening, which has good thermal stability.