准干式电火花强化TC4强化层的耐高温试验研究  

Experimental Study on the High-Temperature Resistance of TC4 Strengthened Layer with Near-Dry Electrical Discharge Machining

作　　者：赵俊领 蔡兰蓉[1,2] 李敏 高忠玉[3] 王井玲 ZHAO Jun-ling;CAI Lan-rong;LI Min;GAO Zhong-yu;WANG Jing-ling(School of Mechanical Engineering,Tianjin Vocational and Technical Normal University,Tianjin 300222,China;Tianjin Key Laboratory of High Speed Cutting and Processing,Tianjin 300222,China;Tianjin Hanhai Lanfan Ocean Technology Co.,Ltd.,Tianjin 300457,China)

机构地区：[1]天津职业技术师范大学机械工程学院,天津300222 [2]天津市高速切削与重点加工实验室,天津300222 [3]天津瀚海蓝帆海洋科技有限公司,天津300457

出　　处：《材料保护》2021年第11期53-56,共4页Materials Protection

基　　金：国家自然科学基金项目(No.51301121,51305301);天津市高校创新团队培养计划(TD12-5043);天津职业技术师范大学校级项目(KJ1704)资助。

摘　　要：为了揭示TC4强化层的耐磨性能随高温的变化趋势,对混粉准干式电火花强化后的钛合金强化层进行耐高温试验,并对强化层在不同温度及不同保温时间下裂纹的萌生和扩展进行统计分析,测量强化层冲击前后磨损量的变化。结果表明:强化层受高温保温后,微观组织花瓣状强化相有裂纹萌生和扩展。在650℃条件下,裂纹从花瓣状强化相尖端萌生扩展,之后向瓣身扩展,但是向瓣身扩展量很小;在750℃条件下,裂纹从瓣身萌生,之后向花瓣顶端扩展,出现分叉并进一步扩展,花瓣撕裂。650℃条件下裂纹平均总长度比750℃的要低。经高温试验后,强化层的磨损量均升高,最大升高至原来的2倍左右,但仍低于钛合金基体材料的磨损量;750℃高温试验后强化层抗磨损性能的降低量大于650℃的。For revealing the change trend of the wear resistance of TC4 strengthened layer with high temperature,the high temperature resistance test of titanium alloy strengthened layer after powder mixed near-dry electrical discharge machining(EDM)treatment was carried out.The initiation and propagation of crack of the strengthened layer at different temperature and holding time were statistically analyzed,and the change of wear amount of the strengthened layer before and after impact was measured.Results showed that crack initiation and propagation occurred in the petal-like strengthening phase in micro structure,after the layer was preserved under high temperature.Under 650℃,the crack propagated from the tip of the petal-like strengthening phase and then expanded to the petal body,but the expansion to the petal body was very small.Under 750℃,the crack initiated from the petal body and extended top of the petal body,crack bifurcation appeared and further extended,then the petal tore.In addition,the average total length of crack under 650℃was lower than that under 750℃.After high-temperature experiment,the wear amount of the strengthened layer increased,and the maximum was about 2 times of the original value,but still lower than that of the titanium alloy substrate material.Besides,the decrease amount of the wear resistance of the strengthened layer after the high-temperature test at 750℃was greater than that at 650℃.

关 键 词：电火花强化 TC4钛合金 耐高温性能 裂纹萌生和扩展 花瓣状强化相 磨损量 

分 类 号：TG178[金属学及工艺—金属表面处理]