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1.
The fracture behavior of a ceramic reinforced metal-base coating prepared by high velocity arc spraying (HVAS)technology in three-point bending test was studied.Moreover,finite element analysis(FEA)was adopted to analyze the stress distribution in the crack front.It can be found that the crack norrnal to the interface in the coatings occurred at the location where a fixed moment of force was reached.So the critical moment can be taken as thecoating cracking criterion,which was confirmed by FEA results.In addition,the stress levels at three different locations where cracks occurred near the interface are almost the same.The results will provide reference for the design of coatings and the structure integrity evaluation of coating/substrate systems. 相似文献
2.
JU Jian-hua XIA Yi-ben ZHANG Wei-li LU Yu WANG Lin-jun SHI Wei-min School of Material Science Engineering Shanghai University Shanghai China National Lab for Infrared Physics. Shanghai Institute of Technical Physics Chinese Academy of 《上海大学学报(英文版)》2000,(Z1)
l IntroductionDLC film is one of coating materials that has highhardness and good wear-resisbot PrOPerlies. When thefilm is deposited on low haulness substrates with thedifferent YOung's model and expansion coefficient, ahigh stress occurs in the film, which resulted in thedecrement of the adherence of the film and the filmspliting or carking['~4]. In order to improve theadherence of DLC film on the soft subside, the mostcommon method is tO colltrol the iIYIPurities, such as H,St, N and… 相似文献
3.
Micro-indention and finite element method (FEM) are used to study the stress at the interface between diamond-like carbon
(DLC) film and mercury cadmium telluride (MCT) substrate, with different coating thickness, deposition temperature and indention load.
The FEM simulation results show that when Young＇s modulus ratio of the coating to the substrate Ec/Es相似文献
4.
CAO Pin-lu LIU Bao-chang YIN Kun ZHANG Zu-pei 《浙江大学学报(A卷英文版)》2006,7(8):1318-1323
INTRODUCTION Polycrystalline diamond compacts (PDC), con-sisting of a polycrystalline diamond (PCD) layer on a WC-Co substrate, and having high hardness and abrasive resistance, are used in a variety of drilling and machining applications (Farhad, 2001; Sadi and Muzaffer, 2001). However, due to differences of thermal and mechanical properties in diamond and WC-Co substrate, residual thermal stresses develop in regions near the interfaces during fabrication. The diamond coating exhib… 相似文献
5.
高强度螺栓断裂失效分析 总被引：2，自引：0，他引：2
卢洪 《福建工程学院学报》2009,7(4)
借助化学分析、金相检验、扫描电镜和力学性能测试等手段对发生断裂的高强度螺栓的显微组织、力学性能、宏观和微观断口形貌等进行了研究.结果表明,螺栓在表面处理过程中,产生氢致裂纹,在应力作用下,发生氢脆断裂. 相似文献
6.
赵升升 《深圳职业技术学院学报》2012,(3):51-54
采用电弧离子镀工艺,调节N2分压制备了系列（Ti,A1）N硬质涂层,研究了不同N2分压对涂层表面形貌、相结构、成分及力争性能的影响．结果表明,当氮气分压较低时,涂层金属相含量较高,涂层硬度和残余应力较低,膜／基结合力较高,涂层耐磨性较差;当氮气分压较高时,涂层氮化物相含量较高,涂层硬度和残余应力较高,膜／基结合力偏低,涂层耐磨性很强． 相似文献
7.
建立了模拟涂层残余应力的数学模型,对等离子喷涂不同厚度NiCrAl/Cr2O3-8%TiO2涂层的残余应力进行了模拟,模拟结果表明:由于涂层与基体的热膨胀系数不匹配等原因,在界面等区域存在严重的应力集中,涂层内部的残余应力水平,随涂层厚度增加而增加,涂层中的径向、轴向、切向应力均为压应力,径向应力是最主要的应力。 相似文献
8.
赵连华 《洛阳工业高等专科学校学报》2007,17(1):15-17
缺口的应力应变状态对结构的断裂影响很大,是钢结构断裂分析和设计中研究的重点.由于一般构件的几何形状和荷载状态复杂,难于对缺口尖端的应力应变状态得到理论解.利用ANSYS软件对受拉平板缺口尖端三维应力状态进行了有限元分析,获得了钢结构缺口尖端的应力分布规律. 相似文献
9.
The characteristics of acoustic emission(AE)signals given off in the course of the failure of a concrete structure is explored based on the laboratory experiments with concrete specimens.It is observed that the failure of a concrete structure experiences three stages divided by two inflexion points on the AE event curve,which are sequentially no damage,damage initiation and propagation,and major failure stages.In the first stage,existing micro cracks and defects are compacted by loading. but no damage propagated,hence few AE signals are detected,and it appears that there exists a nearly linear relationship between the relative stress and relative strain.In the second stage,the AE event frequency increases implying that micro cracks begin to emerge inside the concrete structure,which is consistent with the damage mechanics.When the load is over 80% of that breaks the structure,i.e.the maximum load,there is a vertical jump on the AE event count curve,which suggests that the failure propagation speeds up.After the second inflexion point,the AE event density increases faster than before,and there is another jump just before breaking,which indicates a quick propagation stage.These findings are valuable for evaluating the damage situations,and for studying and monitoring the dynamic process of the failure behaviors of a concrete structure. 相似文献
10.
郭晓霞 《深圳职业技术学院学报》2013,12(3):27-30
电火花沉积工艺（ESD）是一种微弧焊工艺,电极材料沉积到基体表面,并于基体呈冶金结合．本文以冷作模具钢Cr12MoV为基体材料,利用电火花沉积对局部区域进行修复．研究了影响沉积层质量和沉积率的工艺参数,其中包括电容、电压和保护气．实验结果显示,虽然随着电容和电压的增大,沉积率提高,但同时也会使沉积层中的微裂纹和孔洞增加．因此,只有合理选择沉积工艺参数,才能达到一定沉积率的同时保证沉积层的质量． 相似文献
11.
赵连华 《常熟理工学院学报》2007,21(2):31-33
裂纹的应力应变状态对结构的断裂影响很大,是钢结构断裂分析和设计中研究的重点。由于一般构件的几何形状和荷载状态复杂,难于对裂纹尖端的应力应变状态得到理论解。本文利用ANSYS软件对受拉平板裂纹尖端三维应力状态进行了有限元分析,获得了钢结构裂纹尖端的应力分布规律。 相似文献
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Titaniumalloyisakindofdesirablemetallicbioma terialforimplantingandrepairingbodyhardtissuesduetoitsbetterbiocompatibilityandmechanicalproper ties[1,2 ] .However ,itcansuffercertaindisadvantages ,suchaspoorosteoinductive ,andlowcorrosivewearresis tance .So ,itisveryimportanttoimprovethejointprop ertiesbetweentitaniumalloyandhumanbody .Hydrox yapatite(HAP)isknowntobebiocompatibleandtoformadirectbondwiththeneighboringbonesduetoitscrys tallographicalandchemicalsimilaritywithvariouscalci fiedtissu… 相似文献
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钢板在精轧时开裂,采用金相显微镜和电子探针对开裂钢板进行了观察和分析。结果表明开裂钢板的板厚中心区域存在Mn等元素偏析并观察到较多聚集分布的夹杂物和严重的马氏体偏析条带;分析认为Mn等元素偏析导致马氏体和聚集分布的夹杂物的产生,而马氏体相变属于非扩散型相变,相变时发生较大的体积膨胀,产生较大的内应力,同时夹杂物的存在为裂纹的产生提供裂纹源,二者共同作用导致裂纹产生并扩展至开裂。 相似文献
14.
阐述了采用nAERO辅助气溶胶薄膜沉积技术制备TCO镀膜玻璃时,在TCO玻璃生产线上出现的玻璃连续炸裂的问题,通过分析和多次对加热炉温度曲线、气浮台高度、镀膜腔室尾气排放量、加热炉与镀膜腔室间隙等工艺及设备调整,对可能存在的原因逐一排查,最终确定炸裂的主要因素,并加以改进,使离线式TCO镀膜玻璃炸裂问题得到了最终解决。 相似文献
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应力腐蚀断裂是焊接结构断裂失效的重要原因之一,这种断裂失效呈脆断特点,易导致灾难性后果.探讨应力腐蚀裂纹的产生、开裂的机理及其影响因素,并提出控制焊接结构发生应力腐蚀断裂的措施. 相似文献
16.
Scratch test and friction test were performed to evaluate the internal and external interface behaviors of TiAlSiN coating, respectively. The critical compressive and shearing stress of coating failure during scratch test were calculated and the values are 30.84 MPa and 4.98 MPa respectively. The average friction coefficients of TiAlSiN coating against 2Cr12Ni4Mo3VNbN steel are 0.70 (sliding speed 50 m/min), 0.63 (sliding speed 100 m/min), and 0.81 (sliding speed 150 m/min). The elements diffusion was analyzed by EDS. Al and Si element of coating material diffuse to the steel disc, except Ti element. The oxidation decreases with the increase of sliding speed, but the adhesion increases with the increase of sliding speed. More Al element diffuses to the steel disc at the high sliding speed, but the diffusion of Si element keeps almost constant at different sliding speeds. 相似文献
17.
高温开裂已经成为沥青路面的主要危害之一。橡胶沥青是良好的沥青改性剂,其具有吸收应力,改善沥青高温性能、延长路面使用寿命、延缓反射裂缝等优点。利用ABAQUS有限元软件,选取15℃、20％和60℃下沥青路面的热特性参数,分析在不同温度下橡胶沥青应力吸收层对半刚性基层路面结构和柔性基层路面结构的应力应变规律,推荐合理的沥青路面结构层设计参数,为工程实践提供理论依据。 相似文献
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用高能球磨制备等原子比铁(Fe)钴(Co)镍(Ni)铁镍钴复合粉体,用激光熔覆方法制备复合粉铁镍钴体合金涂层。用OM、HV、XRD、SEM、EDS、SVET等对复合粉体及熔覆合金层进行了组织表征及性能测试。结果表明,复合粉体经3 h高能球磨后均匀细化,平均尺寸从35μm到15μm左右,镍晶格有一定畸变,有新相Co3Fe7产生;用优化后的激光熔覆工艺激光功率2000 W,激光扫描速度10 mm/s,保护Ar气流速度12 L/min制备中熵熔覆合金FeCoNi涂层;XRD、SEM、EDS表明熔覆层合金是单一的面心立方(FCC)相,Fe,Co,Ni成分均匀分布,没有金属间化合物产生;熔覆层的HV约是243,在0.5 mol/L氯化钠溶液中熔覆层的SVET表明耐腐蚀性能好。 相似文献
20.
本文建立了热残余应力分析的数学模型，采用数值方法对陶瓷涂层材料的热残余应力进行了分析，得出了金属基底的弹性性能、过渡层的厚度和陶瓷涂层的孔隙率对热残余应力的影响，为含FGM的陶瓷涂层材料的优化提供了一种理论分析方法。 相似文献