中文摘要：

研究了表面纳米化预处理对Ti-6Al-4V合金渗硼的影响。采用表面机械研磨处理（SMAT）在Ti-6Al-4V合金表面预先制备出一层纳米晶层,随后采用粉末渗硼法对纳米晶样品进行渗硼处理,并利用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）和微观硬度测试仪等对渗硼层的相组成、结构形貌、显微硬度和韧性进行了表征与测试。结果表明：表面纳米化预处理可以显著增强Ti-6Al-4V合金低温渗硼动力学,降低渗硼温度。与未处理的高温渗硼样品相比,纳米化预处理样品低温渗硼层硬度和耐磨性略有下降,但仍满足工业应用要求。渗层脆性级别评定表明表面纳米化预处理可以有效降低渗硼层的脆性。

英文摘要：

Effects of surface nanocrystallization pretreatment on boronizing of Ti-6Al-4V alloy were investigated. A nanocrystalline layer was fabricated on the surface of the Ti-6Al-4V alloy by surface mechanical attrition treatment（ SMAT）. Then the nanocrystallized samples were subjected to powder boronizing. The phase composition,microstructure,microhardness and toughness of the borided layer were studied by means of X-ray diffraction（ XRD）,scanning electron microscopy（ SEM）,transmission electron microscopy（ TEM） and microhardness test. The results show that the surface nanocrystallization pretreatment can significantly enhance the low temperature boronizing kinetics of the Ti-6Al-4V alloy,and reduce the boronizing temperature. Compared with the untreated high temperature boronizing sample,the hardness and wear resistance of the low temperature boronizing layer of the nano-pretreated sample decrease slightly,but still meet the requirements of industrial application. The evaluation of the brittleness of the layer shows that the surface nanocrystallization pretreatment can effectively reduce the brittleness of the boronizing layer.