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为了提高商业纯钛(CP)的疲劳和摩擦两种性能,开发了低温渗氮工艺。冷轧作为离子渗氮的前处理,能获得细晶粒,加速氮向材料中扩散。用显微维氏硬度计、光学显微镜、扫描电镜(SEM)、X射线衍射(XRD)和背散射电子衍射技术(EBSD)表征冷轧前处理的渗氮样品的显微组织。在大于600℃渗氮的表面上形成钛氮化合物(TiN和Ti2N)。在冷轧预处理的CP钛渗氮后生成的化合物层比单一渗氮的更厚,因此有更高的硬度。低温渗氮(600℃)的试样以应力比R=0.1,室温下做4点弯曲疲劳试验,能抵制晶粒粗化。此外,根据观察显微组织和断裂表面探讨了渗氮CP钛的疲劳断裂机制。
In order to improve the fatigue and friction properties of commercial pure titanium (CP), a low temperature nitriding process was developed. As a pretreatment of ion nitriding, cold rolling can obtain fine grains and accelerate the diffusion of nitrogen into the material. The microstructure of nitriding samples pre-cold-rolled was characterized by micro Vickers hardness tester, optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD) and backscattered electron diffraction (EBSD) Titanium nitrogen compounds (TiN and Ti2N) are formed on the surface nitrided at more than 600 ° C. The nitrided CP titanium after cold-rolled pre-treatment produces a thicker compound layer than nitriding alone and therefore has a higher hardness. Low temperature nitriding (600 ℃) specimens with stress ratio R = 0.1, 4:00 bending fatigue test done at room temperature, to resist grain coarsening. In addition, the mechanism of fatigue fracture of nitrided CP titanium was discussed based on the observed microstructure and fracture surface.