摘要
工程陶瓷零件的亚表面损伤严重影响其可靠性和使用寿命,因此探究了磨削温度对氮化硅陶瓷表面裂纹扩展的影响。首先,通过K型热电偶测温技术获得磨削参数与磨削温度的关系;其次,通过陶瓷片磨削试验获得陶瓷内部亚表面裂纹扩展情况;最后,得出磨削温度对裂纹扩展的改善机制。试验结果表明,随着磨削速度、磨削深度的增加,磨削温度增大;随着进给速度的增加,磨削温度减小。纵向裂纹在陶瓷内部扩展时会产生与原纵向裂纹扩展方向相同或者相近的新纵向裂纹,新纵向裂纹的路径在残余热应力的作用下会改变方向,出现横向裂纹,当新横向裂纹与原横向裂纹扩展路径相交后,会引起陶瓷表面的断裂和剥落。当磨削温度由456℃增加到1035℃时,裂纹扩展深度先由8.1μm减小到3.8μm后,再增大到19.2μm,在603~732℃时,裂纹扩展深度较小,为3.8~5.6μm。研究表明适当的磨削温度对陶瓷亚表面裂纹扩展有抑制作用。
The subsurface damage of engineering ceramic parts seriously affects its reliability and service life.Therefore,the influence of grinding temperature on the surface crack propagation of silicon nitride ceramics was explored.Firstly,the relationship between grinding parameters and grinding temperature was obtained by K-type thermocouple temperature measurement technology.Secondly,the subsurface crack propagation inside the ceramic was obtained through the ceramic chip grinding experiment.Finally,the improvement mechanism of grinding temperature on crack propagation was obtained.The experiment results show that as the grinding speed and grinding depth increase,the grinding temperature increases;as the feed speed increases,the grinding temperature decreases.When longitudinal cracks propagate inside the ceramic,new longitudinal cracks will generate in the same or similar direction as the original longitudinal cracks.The path of the new longitudinal cracks will change direction under the action of residual thermal stress,and transverse cracks will appear.When the propagation path of new transverse crack intersects the original transverse crack,the ceramic surface will break and peel off.As the grinding temperature increases from 456℃to 1035℃,the crack propagation depth first decreases from 8.1μm to 3.8μm and then increases to 19.2μm.When the temperature is between 603~732℃,the crack propagation depth is smaller,the depth is 3.8~5.6μm.Study has shown that an appropriate grinding temperature can inhibit the growth of subsurface cracks of ceramic.
作者
李霞
LI Xia(Department of Numerical Control,Baotou Iron and Steel Vocational and Technical College,Baotou 014010,China)
出处
《现代制造工程》
CSCD
北大核心
2021年第6期57-62,68,共7页
Modern Manufacturing Engineering
基金
国家自然科学基金项目(51766016)
内蒙古自治区高等学校科学研究项目(NJSY19325)。
关键词
工程陶瓷
磨削温度
表面/亚表面
裂纹扩展
改善机制
engineering ceramic
grinding temperature
surface/subsurface
crack propagation
improvement mechanism
