Surface Strengthening of Ti-6Al-4V Alloy by Glow Plasma Carbonization Process

摘要:

利用辉光等离子渗碳技术对Ti-6Al-4V进行了表面强化处理。等离子气体为氩气，渗碳温度和时间分别为950 ℃和3 h，工作压力为30~35 Pa。为了避免传统气体渗碳过程中易于产生氢脆的现象，用固体石墨棒作为碳源。渗碳结束后，分别利用OM、FESEM和XRD对渗碳层做分析，并在坏-块摩擦磨损试验机上对处理和未处理样品进行摩擦磨损对比实验。结果发现，渗碳层深度约为416 μm，其表面碳化物（TiC和V8C7）提高了合金表面的硬度和耐磨性能。

Abstract:

A glow plasma carburizing technique was applied to strengthen the surface of the Ti-6Al-4V alloy. The alloy was carburized at 950 oC and 30~35 Pa for 3 h using plasma of Ar gas. Graphite rod was employed as carbon supply to avoid the hydrogen brittleness which is common in traditional gas carbonization. The carburized layer was examined by an optical microscope (OM), field emission scanning electron microscope (FESEM), and X-ray diffractometer (XRD). The wear resistance under ring-block wear testing and the surface hardness were evaluated and compared to those for the untreated material. Results show that a carburized layer (416 μm thick), mainly composed of TiC and V8C7, is found. These hard carbides contributed to the imrovement of the hardness and wear resistance.