不同温度下TC21钛合金等离子表面渗Cr层的摩擦磨损性能

Tribological Behavior of Plasma Chromized Layer on TC21 Alloy at Different Temperatures

为提高TC21合金的摩擦磨损性能,采用双辉等离子冶金技术在TC21合金表面制备渗Cr改性层,利用扫描电镜(Scanning electron microscope,SEM),能谱仪(Energy dispersive spectromenter,EDS),显微硬度仪和划痕仪等研究了渗Cr层的组织形貌特征、硬度及结合强度,并在20,300,500℃条件下使用摩擦磨损试验机对基体及渗Cr层的摩擦磨损性能进行对比、探究,并分析磨损机理。结果表明:渗Cr层厚度为30μm,均匀致密,与基体结合力至少能承受64N的垂直载荷;改性层表面硬度超过1 000 HV_(0.1),约为基体的3倍;TC21合金渗Cr后,不同温度下的减摩性能和耐磨性能均得到提高。在室温下TC21基体磨损机理主要是磨粒磨损、粘着磨损和氧化磨损,而渗Cr层的磨损机理主要是磨粒磨损;500℃时基体粘着磨损和氧化磨损程度变得更加严重,渗Cr层磨损机理是剥层磨损和氧化磨损。

To improve the tribological behavior of TC21 alloy,the chromized layer is prepared on its surface by using the double-glow plasma surface alloying technology.The microstructure,element distribution,hardness and adhesion strength of chromized layer are characterized by the scanning electron microscope（SEM）,energy dispersive spectrometer（EDS）,hardness tester and scratch tester,respectively.Using the friction and wear testing machine,the tribological behavior of matrix and chromized layer is explored at different tempertures.The results show that the chromized layer is dense,not cracked and well combined with matrix,and its thickness is about 20μm.The surface micro-hardness of chromized layer is over 1 000HV_（0.1）and gradually decreases with the depth.After chromizing,the general friction coefficient and the specific wear rate of TC21 alloy are reduced at different temperatures,which shows that the antifriction and wear-resistance perform better.The main wear mechanisms of matrix are abra-sion wear,adhesive wear and oxidation wear at 20℃.The wear mechanism is dominated by the abrasion wear at the same temperature.At 500 ℃,the adhesive wear and the oxidation wear become more serious,and the chromized layer wear mechanisms are elamination wear and oxidation wear.