工艺参数对钛/瓷界面组织及性能的影响

应用扫描电镜、能谱、X射线衍射及电子拉伸试验机对钛/瓷界面的微观组织和力学性能进行了研究。结果表明,钛/瓷界面由钛表面氧化膜层和瓷与氧化膜层作用形成的反应层组成,烤瓷工艺参数直接影响钛/瓷界面结构、结合强度和断裂位置。烤瓷温度对钛/瓷界面结合强度影响较大,烤瓷温度为800℃、烤瓷时间为1 min时,钛/瓷界面三点弯曲结合强度为24.7MPa。随着烤瓷温度的提高和烤瓷时间的延长,钛表面氧化膜层和反应层变宽,最终影响钛/瓷界面的结合强度。     

钛表面处理对增强钛/瓷结合强度的影响

为了提高钛/瓷结合强度,通过不同方法对钛表面进行处理,研究了钛表面处理后钛/瓷界面组织及结合强度。试验结果表明,烤瓷前进行钛表面喷砂处理,对增强钛/瓷结合强度的影响并不显著,但对抑制钛/瓷界面裂纹的扩展起到积极作用;钛表面预氧化处理能够在钛表面形成一层均匀的氧化膜,使参与界面反应的TiO2增多,反应层增厚,但预氧化温度对钛/瓷结合强度有重要影响;钛表面磁控溅射Zr中间层能够抑制钛表面生成过厚氧化层,而中间层厚度对钛/瓷结合强度也有较大影响。     

预氧化处理对钛瓷冠界面结合影响的研究

分析研究了预氧化处理工艺对钛瓷冠修复体钛－瓷界面结合强度的影响．研究发现：与传统烤瓷修复工艺不同,预氧化处理对钛瓷结合强度无增强作用,且预氧化温度高于５００℃时对钛－瓷结合还会产生不利的影响．同时对我们研制的钛瓷材料进行了评价．     

激光选区熔覆牙科用钴铬钼合金的金瓷结合性研究

为解决传统铸造的钴铬钼烤瓷修复体在临床应用中存在的崩瓷、瓷剥落等问题,对激光选区熔覆（Selective Laser Melting, SLM）技术制作的牙科钴铬钼合金进行了金瓷结合性研究,以探求SLM技术在临床应用的可行性。使用SLM成型机制备金瓷结合、热膨胀系数试样,以铸造钴铬钼合金为对比,借助金相显微镜、扫描电镜、X射线衍射仪、热膨胀仪等分析测试方法,通过对其显微结构、相组成、热膨胀系数、金瓷结合强度及其结合界面的研究来综合评价SLM制作的钴铬钼合金的金瓷结合性。研究结果表明：SLM制作的钴铬钼合金的相组成主要包含FCC结构的α相和HCP结构的ε相,不含针状有害相σ相,且α相的含量达到84%;SLM制作的钴铬钼合金在25℃~500℃的平均线膨胀系数为13.874×10-6 /K,低于同类铸造钴铬钼合金试样,金属基体与陶瓷的热匹配性更好;SLM钴铬钼合金的金瓷结合强度为（36.55±1.78）MPa,明显高于铸造合金（P<0.01）,且数值稳定性更好;钴铬钼合金与陶瓷的断裂模式是粘附开裂,与结合界面处金属与陶瓷润湿性和内生氧化膜形态有关;SEM分析发现SLM制作的烤瓷件合金与陶瓷的润湿情况较好,无微孔等缺陷,内生氧化膜厚度较厚;铸造烤瓷件合金与陶瓷的润湿性较差,存在微孔等缺陷,内生氧化膜的厚度较薄。通过与铸造钴铬钼合金性能对比发现,SLM制作的钴铬钼合金具有更好的金瓷结合性,这为SLM技术在牙科修复临床应用提供参考。     

铁对 C/Cu 复合材料界面特性影响的研究

利用电子显微及X射线衍射仪分析研究了C/Cu复合材料的界面特性及合金元素铁对C/Cu复合材料界面特性的影响.研究表明复合材料界面既无化学反应也无扩散发生,C/Cu界面是物理结合.试验表明,合金元素Fe与碳纤维发生化学反应,使C-Cu界面结合强度明显提高,因此使C/Cu复合材料的强度从592MPa提高到696MPa,横向剪切强度从64MPa提高到84MPa.化学结合型界面是提高复合材料强度的途径之一.     

铁对C／Cu复合材料界面特性影响的研究

利用电子显微及X射线衍射仪分析研究了C／Cu复合材料的界面特性及合金元素铁对C／Cu复合材料界面特性的影响，研究表明复合材料界面既无化学反应也无扩散发生，C／Cu界面是物理结合，试验表明，合金元素Fe与碳纤维发生化学反应，使C-Cu界面结合强度明显提高，因此使C／Cu复合材料的强度从592MPa提高到696MPa，横向剪切强度从64MPa提高到84MPa，化学结合型界面是提高复合材料强度的途径之一。     

SiC颗粒增强锆基非晶材料的组织与变形行为

为获得高强度、低密度且有一定塑性的新型复合材料,在铜模喷铸条件下制备了体积分数分别为6%和10%的SiC颗粒增强Zr_5.05Al₉Ni_4.05Cu_36.45块体非晶合金复合材料.应用x射线衍射仪、透射电镜、材料试验机和扫描电镜分析了复合材料的相组成、微观组织、压缩性能及断口形貌.实验结果表明：界面微观组织的变化对复合材料力学性能有显著的影响.有限的界面反应物ZrC能够增强界面的结合强度,有效地传递应力,从而阻碍剪切带的局域化扩展,促使多重剪切带的萌生,有助于提高合金的强度和塑性.而过量的界面反应则弱化界面的结合强度,致使合金压缩变形时,沿界面迅速开裂,表现为脆性断裂.     

非水反应高聚物–混凝土界面单调剪切特性及本构模拟

土与结构物的界面力学性质一直都是岩土工程探究的热点,为了探究非水反应高聚物与混凝土的界面剪切特性,本文基于单调直接剪切试验研究了竖向应力、剪切速率对高聚物-混凝土界面抗剪强度和剪切模量等特性的影响。试验结果表明:在给定的竖向应力与剪切速率下,随着剪切位移的增加,高聚物-混凝土界面呈现出剪切软化的现象。剪切速率对抗剪强度以及残余强度有一定的影响,对界面剪切模量值有显著影响,随着剪切速率的增加剪切模量值不断减小,减小幅值明显,然而对高聚物-混凝土界面的粘聚力、残余粘聚力、摩擦角以及残余摩擦角影响较小;竖向应力对高聚物-混凝土界面抗剪强度、残余抗剪强度以及剪切模量值有显著影响,并且高聚物-混凝土界面抗剪强度、残余抗剪强度以及剪切模量值随着竖向应力的增加而不断增加。同时,本文系统的公式推导描述了高聚物-混凝土界面的双曲线本构模型的构建过程,并依据相关实验结果初步验证了模型的有效性。     

异种材料扩散连接界面强度分析

本文针对Ａ３＋ＬＹ１２、Ａ３＋Ｃｕ、Ａ３＋Ａ３几种材料组合进行了扩散连接接头的界面剪切强度试验分析;建立了异种材料扩散连接接头残余应力分析模型;讨论了残余应力分布对所选材料组合接头界面剪切强度的影响。结果表明,残余应力对界面剪切强度有显著影响,根据该模型得出的计算结果和实验测试结果吻合程度良好。     

高Ni-Cr合金涂层防护锅炉受热面高温腐蚀的性能研究

针对电站锅炉受热面高温腐蚀的影响,采用电弧喷涂工艺,基体为锅炉受热面常用材料,喷涂国产高Ni-Cr合金涂层,对比FeCrAl涂层和T91材质,研究高温条件下的热腐蚀实验和热震实验,结合腐蚀动力学曲线与金相分析得到的孔隙率,说明国产高Ni-Cr合金在腐蚀防护上具有良好的性能,为今后电厂采用高Ni-Cr合金热喷涂涂层的防高温腐蚀应用提供借鉴.     

Preliminary study on some properties of Co-Cr dental alloy formed by selective laser melting technique

The surface condition, some properties and ion releasing behavior of cobalt-chromium (Co-Cr) dental alloy formed by selective laser melting (SLM) technique were investigated. Before porcelain fused firing, the surface condition of the Co-Cr alloy was observed using a scanning electron microscope (SEM), and then the density and hardness were examined. After porcelain fused firing, the interface of porcelain and alloy was observed, and then the metal-ion release of the samples was tested. SLM technique provides Co-Cr alloy higher hardness than casting method. After degassing-oxidation procedure and porcelain fused firing, the interface of the alloy and porcelain showed excellent combination. Co ion was more than Cr ion released from SLM Co-Cr alloy, the amounts of Co and Cr ions were safe according to ISO security criterion. Considering the properties before and after porcelain fused sintering process, SLM technique is suitable for dental Co-Cr alloy restoration.     

Effect of Interface on Mechanical Property of Steel-mushy Al-20Sn Bonding Plate

1 IntroductionSteel-Al-20Sn bonding plate is an ideal material ofneotype bearing[1-3].Almost one milliontons of this bond-ing plate are needed in machinery and automobile fieldannually[4-6].Forthis bonding plate ,theinterfacial struc-ture is very important .It determines the interfacial me-chanical property.Broadly,there are there kinds of inter-face for steel-Al-20Sn bonding plate .For solid steel plateto solid Al-20Sn bonding plate ,the interface is basicallymade upof Fe-Al solidsolution…     

Ratio of Fe-Al compound at interface of steel-backed Al-graphite semi-solid bonding plate

The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interfacial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interfacial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.     

Ti-6Al-4V/Ni/ZQSn10-10的扩散连接

对钛合金Ti-6A l-4V与锡青铜ZQSn10-10异种金属扩散连接进行了试验研究。利用场发射电镜、能谱仪等对接合区的界面和组织形貌进行了分析比较。结果表明:Ti-6A l-4V/ZQSn10-10直接扩散连接时,由于母材组元的相互扩散和迁移,在交界面附近形成了金属间化合物层,接头强度仅为母材基体强度的30%左右。采用N i做中间层时,避免了母材组元Ti与Cu之间的相互扩散,只存在一定程度的N i分别与两侧的Cu、Ti之间的相互扩散,接头扩散区的组织形貌有了明显的改善。在最佳连接规范(连接温度T=830℃,连接压力p=15 MPa,连接时间t=30 m in)下,可使钛合金与锡青铜牢固地连接,接头强度达到母材基体强度的65%(达155 MPa),且连接试样无明显变形。     

Interface conjunction factors of thermal barrier coatings and the relationship between factors and composition

1 Structure and composition of thermal barrier coatings The thermal barrier coatings (TBCs), having superior properties of heat resistance, corrosion resistance, wear resistances and low heat conductivity, are mainly used in the aeronautic turbines with large thrust force-weight ratio. In TBCs ceramics is covered on the metal matrix in the form of coatings to withstand high service temperature [1]. Today most of the TBCs have the dou-ble-layer- structure of alloy matrix + the bonding laye…     

Thickness of compound layer in steel-aluminum solid to liquid bonding

The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The surface of solid steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. In order to determine the thickness of Fe-AI compound layer at the interface of steel-aluminum solid to liquid bonding under rapid solidification, the interface of bonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationship between bonding parameters (such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time) and thickness of Fe-AI compound layer at the interface was established by artificial neural networks (ANN) perfectly. The maximum of relative error between the output and the desired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacial shear strength of bonding plate (226℃for preheat temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8 s for bonding time), the reasona     

PDC钻头的真空扩散焊中间工艺夹层的选择

为解决PDC钻头用复合片与硬质合金真空扩散焊的工艺关键问题 ,进行了中间工艺夹层的选择实验。结果表明 ,在相同的焊接条件下 ,采用Ni作中间工艺夹层比Cu作中间工艺夹层的焊缝剪切强度高 ;在试验的工艺参数下 ,得出了Ni中间工艺夹层厚度与焊缝剪切强度的关系 ,借助电子探针能谱分析手段研究了焊缝结合面两侧原子的扩散行为 ,指出以 45 μm冷扎态纯Ni箔作中间工艺夹层 ,使焊缝结合面处的Ni扩散深度达到 1 1 μm时 ,焊缝剪切强度可达 485MPa。