摩擦轧压表面处理及退火处理中纯钛的微观组织与织构演化

摘要

Commercial purity and high purity titanium sheets were initially strained by a new technique,named as friction roll surface processing (FRSP).Severe strain was imposed into the surface layer and strain gradient was formed through the thickness of the sheet.The microstructure and texture in as-strained state were investigated by optical microscopy and X-ray diffraction technique.On the surface of the sheets,ultra-fine grains were found to have a sharp texture with a preferred orientation strongly related to the FRSP direction.The evolution of microstructure and crystallographic texture of FRSPed samples during recrystallization were also studied by electron back-scattered diffraction (EBSD) technique after being annealed at selected temperatures and time.The results indicated that the preferred orientations resulting from FRSP and annealing in the surface layer were formed during rolling and its recrystallization textures were reduced by FRSP.In addition,the texture evolved stably without change in main components during the annealing.%通过一种新的摩擦轧压表面处理工艺(FRSP)对纯钛板材表面进行加工,引入的应变沿材料厚度方向成梯4度分布.采用光学显微镜、X射线衍射对FRSP加工后的纯钛的微观组织进行观察发现在钛材表面形成了超微细晶粒,且具有明显织构,其方向与FRSP的加工方向有关.另外,对FRSP处理后的钛材在不同温度和时间下进行退火处理,通过EBSD研究织构的形成及其在退火过程中的演变规律.结果表明:在低温退火过程中,钛板材表层主要存在FRSP后形成的织构,而原有的典型轧制织构减少,可见,通过FRSP及后续退火可有效地控制钛材表面的微观组织与织构.