涂层在冲击式压入条件下的失效机理及声发射信号特征
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摘要
冲击式压入比静载式压入更易于诱导涂层失效,获得离散性较小的声发射信号,也容易制作成小型化便携设备。为了建立冲击式压入声发射信号与涂层结合强度的映射模型,揭示不同类型涂层在冲击式压入时的失效机理及声发射信号特征十分重要。采用配有声发射检测装置的冲击式压入设备分别对金属基体、NiCr涂层、有粘结底层Al_2O_3涂层及无粘结底层Al_2O_3涂层进行试验,分析了压痕的表面形貌、三维形貌、压痕尺寸及横截面形貌,测量了涂层的结合强度,并对能量计数、幅值、波形电压等声发射信号进行了分析。结果表明:在冲击式压入条件下NiCr涂层以界面开裂为主,无粘结底层Al_2O_3涂层以涂层断裂为主,并伴有一定的界面开裂,有粘结底层Al_2O_3涂层具有前两类涂层的共同特点;冲击过程中产生的声发射能量计数及波形电压对涂层的结合强度较为敏感,可用于涂层结合强度的表征。
Comparing with static load indentation,impact indentation is easier to induce coating failure,and to obtain less discrete acoustic emission signals and to make miniaturized portable devices as well. In order to establish a mapping model between the acoustic emission( AE)signal of impact indentation and the bonding strength of coatings,it is very important to reveal the failure mechanism and AE signal characteristics of different coatings during impact indentation. In this paper,the impact indentation equipment equipped with acoustic emission detection device was used to test the metal substrate,Ni Cr coating,Al_2O_3 coating with bonded layer and Al_2O_3 coating without bonded layer,respectively. The surface topography,three-dimensional morphology,indentation size and cross-sectional morphology of the indentation were analyzed.The bonding strength of the coating was measured. The acoustic emission signals such as energy counting,amplitude,waveform voltage and so on were analyzed. Results showed that under the impact indentation condition,the Ni Cr coating mainly showed cracking at the interface. Al_2O_3 coating without bonded layer presented the fracture failure with a certain interface cracking,and Al_2O_3 coating with bonded layer had the common characteristics of the first two kinds of coatings. The acoustic emission energy counts and waveform voltages produced during the impact process were sensitive to the bonding strength of the coating,which could be used to characterize the bonding strength of the coating.
Comparing with static load indentation,impact indentation is easier to induce coating failure,and to obtain less discrete acoustic emission signals and to make miniaturized portable devices as well. In order to establish a mapping model between the acoustic emission( AE)signal of impact indentation and the bonding strength of coatings,it is very important to reveal the failure mechanism and AE signal characteristics of different coatings during impact indentation. In this paper,the impact indentation equipment equipped with acoustic emission detection device was used to test the metal substrate,Ni Cr coating,Al_2O_3 coating with bonded layer and Al_2O_3 coating without bonded layer,respectively. The surface topography,three-dimensional morphology,indentation size and cross-sectional morphology of the indentation were analyzed.The bonding strength of the coating was measured. The acoustic emission signals such as energy counting,amplitude,waveform voltage and so on were analyzed. Results showed that under the impact indentation condition,the Ni Cr coating mainly showed cracking at the interface. Al_2O_3 coating without bonded layer presented the fracture failure with a certain interface cracking,and Al_2O_3 coating with bonded layer had the common characteristics of the first two kinds of coatings. The acoustic emission energy counts and waveform voltages produced during the impact process were sensitive to the bonding strength of the coating,which could be used to characterize the bonding strength of the coating.
引文
[1]王海军.热喷涂工程师指南[M].北京:国防工业出版社,2010:203-204.
[2] GU L J,FAN X Z,ZHAO Y,et al. Influence of ceramic thickness on residual stress and bonding strength for plasma sprayed duplex thermal barrier coating on aluminum alloy[J]. Surface and Coatings Technology,2012,206(21):4 403-4 410.
[3] STALLARD J,POULAT S,TEER D G. The study of the adhesion of Ti N coating on steel an titanium alloy substrates using a multi-mode scratch tester[J]. Tribology International,2006,39(2):159-166.
[4] ZHANG H,LI D Y. Determination of interfacial bonding strength using a cantilever bending method with in situ monitoring acoustic emission[J]. Surface and Coatings Technology,2002,155(2/3):190-194.
[5] GUO S Q,MUMM D R,KAGAWA A M,et al. Measurement of interfacial shear mechanical properties in thermal barrier coating systems by a barb pullout method[J]. Scripta Materialia,2005,53(9):1 043-1 048.
[6] CHALKER P R,BULL S,RICKERBY D S. A review of methods for the evaluation of coating-substrate adhesion[J].Materials Science and Engineering A,1991,140:583-592.
[7]宋亚南,徐滨士,王海斗,等. Al2O3陶瓷涂层尖端受载下的声发射信号参量分析[J].声学学报,2013,38(4):413-418.
[8]王海军,刘明,宋亚南,等.声发射检测压入法评价涂层的结合强度[J].材料热处理学报,2014,35:190-194.
[9] SONG Y N,XU B S,WANG H D,et al. Failure process analysis of plasma sprayed coatings under tip load based on acoustic emission signals[J]. Surface Engineering,2014,30(9):675-682.
[10]王海军,徐滨士,张平,等.超音速等离子喷涂枪:01101077. 0[P]. 2001-07-04.
[11]王海军.热喷涂实用技术[M].北京:国防工业出版社,2006:45.
[12] HEINKE W,LEYLAND A,MATTHEWS A. Evaluation of PVD nitride coatings,using impact,scratch and Rockwell-c adhesion test[J]. Thin Solid Films,1995,270:431-438.
[13] LI M,SAMUEL L,JOHN S. A method to determine the spherical indentation contact boundary diameter in elasticplastic materials[J]. Mechanics of Materials,2014,69:213-226.
[2] GU L J,FAN X Z,ZHAO Y,et al. Influence of ceramic thickness on residual stress and bonding strength for plasma sprayed duplex thermal barrier coating on aluminum alloy[J]. Surface and Coatings Technology,2012,206(21):4 403-4 410.
[3] STALLARD J,POULAT S,TEER D G. The study of the adhesion of Ti N coating on steel an titanium alloy substrates using a multi-mode scratch tester[J]. Tribology International,2006,39(2):159-166.
[4] ZHANG H,LI D Y. Determination of interfacial bonding strength using a cantilever bending method with in situ monitoring acoustic emission[J]. Surface and Coatings Technology,2002,155(2/3):190-194.
[5] GUO S Q,MUMM D R,KAGAWA A M,et al. Measurement of interfacial shear mechanical properties in thermal barrier coating systems by a barb pullout method[J]. Scripta Materialia,2005,53(9):1 043-1 048.
[6] CHALKER P R,BULL S,RICKERBY D S. A review of methods for the evaluation of coating-substrate adhesion[J].Materials Science and Engineering A,1991,140:583-592.
[7]宋亚南,徐滨士,王海斗,等. Al2O3陶瓷涂层尖端受载下的声发射信号参量分析[J].声学学报,2013,38(4):413-418.
[8]王海军,刘明,宋亚南,等.声发射检测压入法评价涂层的结合强度[J].材料热处理学报,2014,35:190-194.
[9] SONG Y N,XU B S,WANG H D,et al. Failure process analysis of plasma sprayed coatings under tip load based on acoustic emission signals[J]. Surface Engineering,2014,30(9):675-682.
[10]王海军,徐滨士,张平,等.超音速等离子喷涂枪:01101077. 0[P]. 2001-07-04.
[11]王海军.热喷涂实用技术[M].北京:国防工业出版社,2006:45.
[12] HEINKE W,LEYLAND A,MATTHEWS A. Evaluation of PVD nitride coatings,using impact,scratch and Rockwell-c adhesion test[J]. Thin Solid Films,1995,270:431-438.
[13] LI M,SAMUEL L,JOHN S. A method to determine the spherical indentation contact boundary diameter in elasticplastic materials[J]. Mechanics of Materials,2014,69:213-226.