摘要
滑动摩擦表面形成变质层是工程应用中的一种常见现象，但对其成因、结构特征和摩擦学性能等（特别是在润滑条件下）的研究至今却还很少。因此，在３２号机械油润滑下，利用销－环式磨损试验机，对含碳量为０．７５％（ｗｔ）的７０Ｓｉ２ＭｎＣｒ钢与偶件５２１００钢环对磨后的表面变质层进行了系统研究。结果表明，无论试样基体是马氏体组织还是奥氏体＋贝氏体混合组织，摩擦表层的形貌、相组成和成分等都有质的变化，明显发生了αγ相变，形成稳定的摩擦奥氏体量最高达到６２．６％。变质层由表亚层、次亚层和严重碎化变形层所组成，其中具有不同特征的两个亚层组成“白层”结构，是超细晶粒的摩擦奥氏体和摩擦马氏体的混合组织。摩擦磨损过程中，摩擦表面变形越大，温升越高和稳定氧化膜的形成时间越长，“白层”越厚。“白层”组织为高密度位错网络和胞状结构，而且变质层中的碳大量向表亚层扩散偏聚，故其硬度高，抗回火稳定性好，抗粘着磨损性能优异。研究结果对延长机械零部件的使用寿命具有重要的指导意义。
The formed worn layer on sliding frictional surface is a common phenomenon inengineering appllcation, however,its forming reason,microstructure feature as well as wearbehavior(especially under lubricated sliding)was seldom studied up to now. The characteristics ofsliding worn layer forming on the surface of 70Si 2MnCr steel pins to mating 52100 steel ring wassystematically studied by means of pin-on-ring wear testing machine with No.3 2 mechanical oillubricant. The results showed that new changes of morphology , phase structure as well ascomposition in worn layer of pins with matrix microstructure of martensite or austenite-bainite dualphase occurred ,αγphase transformation obviously took place during sliding wear,then stablefrictional austenite of amount up to 62.6%was formed.The structure of worn layer was made upof three layers with different morphology; among them,the subsurface layer and hypo-layer formthe structure of “white layer”,which was a mixed microstructure of frictional martensite andfrictional austenite with extra-fine grain(nanocrystalline).During sliding wear,the more thedeformation,the higher the temperature,the longer the time of developed stable oxide film,theth1cker is“ white layer”on frictional surface. The main features of “white layer”microstructureare high density of tangled dislocation ar rays and dislocation cells,high microhardness up to HV0.0511 00-1600, high tempering stability, excellent anti-adbesion and wear resistance,and more,much diffusion as well as concentration of carbon atoms from hypo-layer to subsurface layer.Theseresults is of practical valuable to raise the working life of mechanical pieces.
出处
《摩擦学学报》
EI
CAS
CSCD
北大核心
1995年第3期224-229,共6页
Tribology
基金
煤矿部煤炭科学基金
清华大学摩擦学国家重点实验室基金
关键词
润滑
滑动摩擦
表面变质层
lubrication, sliding friction,worn layer,frictional austenite, white layer
