空蚀破坏的微观过程研究 薛伟.pdf

29 2 机　械　工　程　材　料 Vol. 29　No. 2 2005 2 Materials　for 　Mechanical　Engineering Feb. 2005 1 2 , (1. 哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨 150001; 2. 哈尔滨大电机研究所, 黑龙江哈尔滨 150040) 　:通过空蚀试验和扫描电镜 析对空蚀试样的破坏过程进行了研究, 进行了微观点跟踪 观察。结果表明:在金属表面产生空蚀针孔, 在随后大量气泡溃灭作用下, 针孔壁逐渐小块剥落,形 成空蚀坑, 当空蚀坑相互连接时,原始表面全部剥落,新的空蚀针孔和空蚀坑又重新形成,使金属表 面层层剥落。确定单 个气泡溃灭产生的微射流是在金属表面造成空蚀针孔的原因,而空蚀坑的形 成则是疲劳裂纹萌生和扩展的结果。 :空蚀;水轮机;叶片材料;微观形貌 :TG172. 9　　　:A 　　　:100-0 3738(2005)02-0059-04 The Micro-cours of the Cavitation Erosion 1 2 XUE Wei , CHEN Zhao-yun (1. Harerbin Institute of Technology, Harbin 150001, hina; 2. Harerbin Institute of Large Electrical Machinery, Harbin 150040, hina) Abstract:By long gterms of cavitation test and a great amount of microanalysis with SEM, the destroyng course of samples under cavitation testing w as studied. According to the changing course of the micr-o appearance of samples, the damaging course of cavitation erosion is determined. First cavitio-n pinholes appear on the sample surface. Then the small pieces peel off from pinhole w alls and pinholes develop into cavitation pit s. After cavitation pits cover all the surface of samples, the previous surface peels off from the new surface repeatedly. It is confirmed that the cavitation pinholes are formed with the micro-liquid jet produced by bubble collapse. The cavitation pits are the results of initiation and grow th of fatigue cracks. Key words:cavitation;hydraulic turbine;blade material;micr-o appearance 1　　 2　 , , , , ZG20SiMn Q235。