固體潤滑涂層的損傷裂紋演變及其摩擦學特性研究
發(fā)布時間：2018-07-31 13:49
【摘要】：先進表面工程技術作為現(xiàn)代工業(yè)發(fā)展的關鍵技術之一,已成為先進制造技術的前沿技術和趕超國際先進水平的重要前沿陣地。表面工程的發(fā)展極大的促進了固體潤滑涂層的進步,在摩擦副表面生成具有優(yōu)良減摩和耐磨性能的固體潤滑涂層,配對成新的接觸副,實現(xiàn)延長摩擦副使用壽命、提高機械效率以及節(jié)約材料的目的。目前,固體潤滑涂層已在現(xiàn)代工業(yè)技術領域,如發(fā)動機和機械傳動等,獲得了廣泛的應用并取得了巨大的經濟價值和社會效應。受涂層和基體材料結構不匹配以及制備工藝影響而產生的較大薄膜涂層殘余應力可能是涂層裂紋和界面分層損傷的催化劑,該問題的理論研究亟待加強,這對固體潤滑涂層的制備具有重要的指導意義。而且,表征評定涂層-基體界面分層以及涂層自身裂紋問題已經成為固體潤滑涂層耐用性和可靠性設計的障礙,迫切需要開展涂層失效的基礎理論研究,并對涂層的失效預測和評價具有顯著的意義。此外,研究固體潤滑涂層潤滑狀態(tài)下的摩擦學特性,并從理論上通過合理的涂層參數(shù)和潤滑設計,避免涂層-基體系統(tǒng)失效的產生,有效地提高摩擦副承載能力和使用壽命,對于開拓涂層摩擦學應用具有重要的理論意義和實際應用價值。本文針對上述固體潤滑涂層-基體系統(tǒng)的界面分層損傷和涂層裂紋演變及其摩擦學特性的科學問題,以物理氣相沉積涂層和鋼基體系統(tǒng)為研究對象,系統(tǒng)性的開展了研究工作,其主要工作和成果總結如下:(1)針對涂層在殘余應力下可能會出現(xiàn)的界面分層和涂層裂紋的問題,建立了考慮粗糙度的涂層-基體系統(tǒng)殘余應力模型,通過擴展有限元技術、J積分法以及內聚力法相結合的手段從理論上研究了涂層在殘余應力下界面分層損傷以及涂層裂紋的演變。表明粗糙面對涂層殘余應力以及基體塑性行為均有較大影響;相比于界面法向應力,分層失效對界面切應力變化更為敏感;而多裂紋時的兩近置的裂紋尖端更容易擴展并最終融合;并且,從力學角度證明沉積一層熱膨脹系數(shù)適中的中間層可以更好的保護整個系統(tǒng)。(2)圍繞涂層-基體界面分層以及涂層自身裂紋的如何評價的問題,通過納米壓痕方法對系統(tǒng)失效情況進行表征,建立了包含內聚力單元的涂層-基體系統(tǒng)壓痕的有限元模型,考察了內聚力屬性、涂層彈性模量以及厚度對涂層裂紋和界面分層的影響,同時揭示了涂層裂紋和界面分層兩者的相互影響規(guī)律。表明增加涂層的內聚力/能雖可有效地防止其裂紋的產生,但同時也增大了界面分層失效的可能性;當界面內聚力處于某臨界值時,界面耐分層能力最小;然而,涂層裂紋對于界面的內聚力屬性變化并不敏感;而彈性模量越小的涂層系統(tǒng)越易免受這些傷害;涂層厚度在影響其裂紋和界面分層臨界載荷方面也存在某一臨界值。(3)利用復合離子鍍膜技術在滲碳鋼基體表面沉積類金剛石(DLC)涂層。使用納米壓痕法對其進行了實驗研究,實時獲得壓頭的載荷-位移曲線。曲線中存在若干跳躍點,意味著系統(tǒng)內部裂紋或界面分層失效的產生。壓痕實驗完成后,通過掃描電子顯微鏡和聚焦離子束系統(tǒng)觀察發(fā)現(xiàn),DLC涂層壓痕處出現(xiàn)了規(guī)則的貫穿厚度的環(huán)形裂紋以及界面分層現(xiàn)象,實驗結果驗證了模擬仿真結果的正確性。最后,通過壓痕結果估算了涂層斷裂韌度和界面結合能。(4)建立了涂層-基體系統(tǒng)微觀彈流潤滑模型,基于Full-system有限元法,研究了涂層的彈流摩擦特性,評價了涂層厚度、涂層彈性模量、工況條件、界面微波谷、表面和界面粗糙度以及多層涂層對系統(tǒng)應力響應的影響,預測了重載下系統(tǒng)可能失效的位置。表明涂層厚度、彈性模量和工況變化會對其彈流特性產生重大的影響;同硬涂層相比,軟涂層的彈流響應對速度和載荷的變化更為敏感;用力學的方式解釋微裂紋一般萌生于界面微波谷處;且油膜壓力以及界面剪應力在較軟和較厚涂層上受表面粗糙度影響更小;同時粗糙界面的剪應力很大程度取決于涂層和基體的匹配度;而功能梯度多層涂層系統(tǒng)可有效預防界面分層以及亞表面點蝕失效。(5)通過四球實驗對比研究了TiN、WC/C和DLC三種固體潤滑涂層的摩擦磨損性能,揭示了它們重載潤滑狀態(tài)下的摩擦學機理。發(fā)現(xiàn)跑合穩(wěn)定后的TiN涂層的摩擦系數(shù)最大,而DLC的最小;TiN涂層磨損失效方式為氧化剝落、WC/C為氧化點蝕,而DLC會在磨痕附近形成轉移膜;則WC/C和DLC涂層表現(xiàn)出較好的減摩耐磨以及跑合特性。
[Abstract]:As one of the key technologies of modern industrial development, advanced surface engineering technology has become an important frontier for advanced manufacturing technology and overtaking international advanced level. The development of surface engineering has greatly promoted the progress of solid lubrication coating, and made solid lubricant with excellent friction reduction and wear resistance on the surface of the friction pair. The slippery coating, paired as a new contact pair, can prolong the service life of the friction pair, improve the mechanical efficiency and save the material. At present, the solid lubrication coating has been widely used in modern industrial technology, such as engine and mechanical transmission, and has achieved great economic value and social effect. The residual stress of large film coating produced by structural mismatch and preparation process may be a catalyst for coating cracks and interfacial delamination damage. The theoretical study of this problem needs to be strengthened. It has important guiding significance for the preparation of solid lubricating coatings. The grain problem has become an obstacle to the durability and reliability design of the solid lubricating coating. It is urgent to carry out the basic theoretical research on the failure of the coating, and have significant significance to the failure prediction and evaluation of the coating. In addition, the tribological characteristics of the solid lubrication coating are studied and the reasonable coating parameters and moistening are used in theory. The slip design avoids the failure of the coating matrix system and effectively improves the bearing capacity and service life of the friction pair. It is of great theoretical and practical value for the development of the coating tribological application. In this paper, the interfacial delamination damage, the evolution of the coating crack and the tribological characteristics of the above solid lubricating coating matrix system are discussed in this paper. The research work of physical vapor deposition coating and steel matrix system is carried out systematically. The main work and results are summarized as follows: (1) the residual stress modes of the coating matrix system considering the roughness of the coating are established to solve the problem that the coating may appear in the interfacial layer and the coating crack under the residual stress. By extending the finite element technique, the J integral method and the cohesive force method, the interfacial stratification damage and the evolution of the coating crack under the residual stress are theoretically studied. It shows that the roughness has a great influence on the residual stress and the matrix plastic behavior of the coating, and the interfacial failure is compared with the interface normal stress. The shear stress change is more sensitive, and the two near crack tip in the multi crack is easier to expand and eventually fuse; and, from the mechanical point of view, the medium layer with moderate thermal expansion coefficient can better protect the whole system. (2) the problem of how to evaluate the coating's self crack and how to evaluate the coating's own crack by the layer of the coating matrix interface. The nano indentation method was used to characterize the failure of the system. The finite element model of the indentation of the coating matrix system containing the cohesive unit was established. The influence of cohesive properties, the elastic modulus and the thickness of the coating on the coating cracks and the interfacial stratification were investigated, and the interaction law of the coating cracks and the interfacial stratification was revealed. The increasing cohesion and energy of the coating can effectively prevent the formation of the crack, but it also increases the possibility of the interfacial delamination failure. When the cohesive force is at a critical value, the interfacial lamination resistance is minimal. However, the coating cracks are not sensitive to the cohesive force properties of the interface, and the less the modulus of the coating, the more the coating system is. It is easy to avoid these injuries; the thickness of the coating also has a certain critical value in influencing the crack and the critical load of the interface layer. (3) the diamond like (DLC) coating is deposited on the surface of the carburized steel substrate by the composite ion plating technology. The experimental study is carried out by the nano indentation method. The load displacement curve of the pressure head is obtained in real time. At several jumping points, it means the failure of the internal crack or interface layer in the system. After the completion of the indentation experiment, it is found through the scanning electron microscope and the focused ion beam system that the circular crack of the regular penetrating thickness and the interfacial stratification appear at the indentation of the DLC coating. The experimental results verify the correctness of the simulation results. Finally, the fracture toughness and interfacial bonding energy of the coating are estimated by the indentation results. (4) the micro elastohydrodynamic lubrication model of the coating matrix system is established. Based on the Full-system finite element method, the Elastohydrodynamic friction characteristics of the coating are studied. The thickness of the coating, the elastic modulus of the coating, the working condition, the interface microwave Valley, the surface and the interfacial roughness are evaluated. The influence of multilayer coating on the stress response of the system is predicted. It is shown that the position of the system may fail under heavy load. It shows that the thickness of the coating, the modulus of elasticity and the change of the working condition have a great influence on its Elastohydrodynamic characteristics. Compared with the hard coating, the Elastohydrodynamic response of the soft coating is more sensitive to the change of velocity and load; the micro crack is explained by mechanical way. The effect of oil film pressure and interfacial shear stress on the surface roughness is smaller than that of the soft and thick coating, and the shear stress of the rough interface depends largely on the matching degree of the coating and the matrix, while the functionally graded multilayer coating system can effectively prevent the interfacial delamination and the subsurface pitting failure. (5) After four ball experiments, the friction and wear properties of three solid lubricating coatings of TiN, WC/C and DLC were compared and studied. The Tribological Mechanism of them under heavy load lubrication was revealed. It was found that the friction coefficient of the TiN coating was the largest and the DLC was the smallest after running in and out. The wear failure mode of TiN coating was oxidation peeling, WC/C as oxidation pitting, and DLC in the grinding mark. The transfer film was formed nearby, and the WC/C and DLC coatings showed good antifriction, wear resistance and running in characteristics.
【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TH117
本文編號：2155773
[Abstract]:As one of the key technologies of modern industrial development, advanced surface engineering technology has become an important frontier for advanced manufacturing technology and overtaking international advanced level. The development of surface engineering has greatly promoted the progress of solid lubrication coating, and made solid lubricant with excellent friction reduction and wear resistance on the surface of the friction pair. The slippery coating, paired as a new contact pair, can prolong the service life of the friction pair, improve the mechanical efficiency and save the material. At present, the solid lubrication coating has been widely used in modern industrial technology, such as engine and mechanical transmission, and has achieved great economic value and social effect. The residual stress of large film coating produced by structural mismatch and preparation process may be a catalyst for coating cracks and interfacial delamination damage. The theoretical study of this problem needs to be strengthened. It has important guiding significance for the preparation of solid lubricating coatings. The grain problem has become an obstacle to the durability and reliability design of the solid lubricating coating. It is urgent to carry out the basic theoretical research on the failure of the coating, and have significant significance to the failure prediction and evaluation of the coating. In addition, the tribological characteristics of the solid lubrication coating are studied and the reasonable coating parameters and moistening are used in theory. The slip design avoids the failure of the coating matrix system and effectively improves the bearing capacity and service life of the friction pair. It is of great theoretical and practical value for the development of the coating tribological application. In this paper, the interfacial delamination damage, the evolution of the coating crack and the tribological characteristics of the above solid lubricating coating matrix system are discussed in this paper. The research work of physical vapor deposition coating and steel matrix system is carried out systematically. The main work and results are summarized as follows: (1) the residual stress modes of the coating matrix system considering the roughness of the coating are established to solve the problem that the coating may appear in the interfacial layer and the coating crack under the residual stress. By extending the finite element technique, the J integral method and the cohesive force method, the interfacial stratification damage and the evolution of the coating crack under the residual stress are theoretically studied. It shows that the roughness has a great influence on the residual stress and the matrix plastic behavior of the coating, and the interfacial failure is compared with the interface normal stress. The shear stress change is more sensitive, and the two near crack tip in the multi crack is easier to expand and eventually fuse; and, from the mechanical point of view, the medium layer with moderate thermal expansion coefficient can better protect the whole system. (2) the problem of how to evaluate the coating's self crack and how to evaluate the coating's own crack by the layer of the coating matrix interface. The nano indentation method was used to characterize the failure of the system. The finite element model of the indentation of the coating matrix system containing the cohesive unit was established. The influence of cohesive properties, the elastic modulus and the thickness of the coating on the coating cracks and the interfacial stratification were investigated, and the interaction law of the coating cracks and the interfacial stratification was revealed. The increasing cohesion and energy of the coating can effectively prevent the formation of the crack, but it also increases the possibility of the interfacial delamination failure. When the cohesive force is at a critical value, the interfacial lamination resistance is minimal. However, the coating cracks are not sensitive to the cohesive force properties of the interface, and the less the modulus of the coating, the more the coating system is. It is easy to avoid these injuries; the thickness of the coating also has a certain critical value in influencing the crack and the critical load of the interface layer. (3) the diamond like (DLC) coating is deposited on the surface of the carburized steel substrate by the composite ion plating technology. The experimental study is carried out by the nano indentation method. The load displacement curve of the pressure head is obtained in real time. At several jumping points, it means the failure of the internal crack or interface layer in the system. After the completion of the indentation experiment, it is found through the scanning electron microscope and the focused ion beam system that the circular crack of the regular penetrating thickness and the interfacial stratification appear at the indentation of the DLC coating. The experimental results verify the correctness of the simulation results. Finally, the fracture toughness and interfacial bonding energy of the coating are estimated by the indentation results. (4) the micro elastohydrodynamic lubrication model of the coating matrix system is established. Based on the Full-system finite element method, the Elastohydrodynamic friction characteristics of the coating are studied. The thickness of the coating, the elastic modulus of the coating, the working condition, the interface microwave Valley, the surface and the interfacial roughness are evaluated. The influence of multilayer coating on the stress response of the system is predicted. It is shown that the position of the system may fail under heavy load. It shows that the thickness of the coating, the modulus of elasticity and the change of the working condition have a great influence on its Elastohydrodynamic characteristics. Compared with the hard coating, the Elastohydrodynamic response of the soft coating is more sensitive to the change of velocity and load; the micro crack is explained by mechanical way. The effect of oil film pressure and interfacial shear stress on the surface roughness is smaller than that of the soft and thick coating, and the shear stress of the rough interface depends largely on the matching degree of the coating and the matrix, while the functionally graded multilayer coating system can effectively prevent the interfacial delamination and the subsurface pitting failure. (5) After four ball experiments, the friction and wear properties of three solid lubricating coatings of TiN, WC/C and DLC were compared and studied. The Tribological Mechanism of them under heavy load lubrication was revealed. It was found that the friction coefficient of the TiN coating was the largest and the DLC was the smallest after running in and out. The wear failure mode of TiN coating was oxidation peeling, WC/C as oxidation pitting, and DLC in the grinding mark. The transfer film was formed nearby, and the WC/C and DLC coatings showed good antifriction, wear resistance and running in characteristics.
【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TH117
【參考文獻】
相關期刊論文 前10條
1 吳軍;金杰;周兆忠;張元祥;;基于納米壓痕試驗的TiN鍍膜有限元分析[J];機械工程材料;2015年04期
2 王海軍;劉明;宋亞南;郭永明;;聲發(fā)射檢測壓入法評價涂層的結合強度[J];材料熱處理學報;2014年S1期
3 付昆昆;鄭百林;殷永柏;胡騰越;葉林;壽大華;;類金剛石薄膜在錐形納米壓頭作用下的斷裂分析[J];北京科技大學學報;2014年02期
4 涂銘旌;歐忠文;;表面工程的發(fā)展及思考[J];中國表面工程;2012年05期
5 楊茂盛;劉秀波;何祥明;王明娣;;固體自潤滑涂層的研究進展[J];材料導報;2011年S1期
6 徐濱士;譚俊;陳建敏;;表面工程領域科學技術發(fā)展[J];中國表面工程;2011年02期
7 弓滿鋒;喬生儒;盧國鋒;姬浩;LYASHENKO B A;;高速鋼上TiN涂層殘余應力的曲率測試和有限元分析[J];機械工程學報;2010年06期
8 張曉化;劉道新;王小鋒;唐賓;;TiN/Ti復合膜與多層膜對Ti811合金高溫摩擦性能及微動疲勞抗力的影響[J];摩擦學學報;2009年04期
9 陳慶川,童洪輝,崔西蓉,劉曉波,耿漫,王經權;多功能復合離子鍍膜機的研制[J];真空;2005年01期
10 溫詩鑄;我國摩擦學研究的現(xiàn)狀與發(fā)展[J];機械工程學報;2004年11期
相關博士學位論文 前2條
1 徐照英;類金剛石（DLC）多層薄膜殘余應力調控及其機械性能研究[D];西南交通大學;2013年
2 張少婧;基于聚焦離子束技術的微刀具制造方法及關鍵技術的研究[D];天津大學;2009年
，本文編號：2155773
本文鏈接：http://sikaile.net/jixiegongchenglunwen/2155773.html
