低压等离子喷涂涂层膜基界面结合能的研究

用努氏界面印痕法 ,对铁基Ni/Fe、镍基Cu/Ni低压等离子喷涂涂层的膜基界面进行界面结合能的研究 ,分析得到涂层界面的断裂表面能。分析得出铁基纯镍Ni/Fe涂层界面的断裂表面能比镍基铜Cu/Ni涂层的断裂表面能高。界面微观分析表明 ,镍基铜Cu/Ni涂层材料疏松 ,膜基界面存在较多裂纹 ,另外涂层和基体观察不到元素扩散层。Ni/Fe涂层界面结合致密 ,约有 2～ 3 μm的元素扩散层。     

金刚石/铜复合材料的界面反应研究

金刚石/铜复合材料(Diamond/Cu)的界面层相比基体与增强体有显著的化学成分变化,具有促进彼此结合、传递载荷的作用。Diamond/Cu复合材料作为热管理材料,热导率是一个关键性能参数。在众多影响因素中,界面对热导率的影响尤为重要。主要研究Diamond/Cu复合材料的界面组成,及成分梯度分布情况。通过扫描电子显微镜(SEM)观察复合材料断口形貌和界面区碳化铬的形态及分布,在近铜端,发现碳化铬以类鳞片状随机零散分布于铜与界面层的互扩散区,界面层处则集中堆垛为层状;采用能谱分析测试仪(EDS)对金刚石/铜复合材料界面区进行元素分布分析,发现各元素具有明显的过渡区域,根据实验结果可估算出过渡区域大约厚700 nm,碳化铬层大约厚400 nm;利用X射线衍射仪(XRD)对金刚石/铜复合材料的界面层进行物相分析,研究表明Diamond/Cu Cr复合材料中界面反应生成的碳化铬以3种形式存在,分别为Cr3C2,Cr7C3,Cr23C6。通过这些实验手段获取界面信息,如界面类型、界面结构、界面组成等,为进一步深入研究Diamond/Cu复合材料界面与性能的关系奠定坚实基础。     

轧制镍基复合板的组织和性能的研究

通过对轧制镍基复合板N08825+X65的结合面宏观及微观形貌进行研究,掌握了轧制镍基复合板的结合面特点和组织形貌,同时研究了C、Ni、Cr、Fe、Mo、Cu、Ti等元素的扩散规律。发现在N08825+X65复合板结合面,C元素的扩散距离最长,超过90μm;Cr和Fe元素的扩散距离达到35μm;Ni、Mo、Cu、Ti等元素扩散距离为20~30μm,而且在结合面形成20μm的结合层。N08825+X65复合板的结合强度很高,其剪切强度达到400 MPa,基层的强度和复合层的耐腐蚀性能均满足使用要求。     

喷涂硬质合金界面的研究

利用电子显微镜观察和研究了超音速喷涂ＷＣＣｏ／弹簧钢界面的微结构特征。发现超音速喷涂使ＷＣＣｏ涂层具有纳米微晶γ粘结相包埋ＷＣ粒子的微观结构，在基体一侧有约２μｍ厚的钨原子扩散层，说明超音速喷涂的涂层与基体间不只是一种机械结合，还有相互间的原子运动。这些微观特征是超音速喷涂ＷＣＣｏ涂层具有高性能的主要原因     

WC-Cu-Ni粉末烧结层的组织与性能研究

采用热压烧结法在45钢基体表面制备WC-Cu-Ni烧结层,通过金相显微镜和扫描电子显微镜观察其微观组织,用能谱仪分析成分,分别测试烧结层的密度、硬度、孔隙率和耐磨性能。结果表明:烧结层中出现大量"熔池"相区,组织呈网格状结构;随着Ni含量的增加,烧结层致密度逐步降低,Ni质量分数为90%时,致密度转而提高;随着Ni含量的增加,烧结层硬度先增大后减小,Ni质量分数为50%时,硬度达到最大值76.6HRA,相对耐磨系数5.2;Cu、Ni之间以扩散迁移的方式向单相α固溶体转变,烧结层与基体界面处发生Fe元素扩散,两者呈冶金结合。烧结层表面的磨损机制主要以磨粒磨损为主,粘着磨损为辅。     

超音速喷涂NiCrBSi涂层表面-界面能谱分析

采用超音速喷涂法在H13热作模具钢表面制备了NiCrBSi涂层,通过扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等分析了涂层表面-界面形貌,化学元素分布和物相组成,并采用面扫描和线扫描对其界面结合机制进行了探讨。结果表明,涂层表面平整,孔隙率较低,出现了非晶和微晶组织,主要由Ni_2Si和Ni_2B相组成;Si,Cr和Ni等主要元素在涂层表面分布均匀,不存在原子聚集现象;涂层的组织结构为Ni-Cr固溶体,其中弥散分布着Ni2Si,Ni_2B和Cr与C结合生成的硬质化合物,Cr_7C_3是涂层的主要硬质相;Ni,Cr,Si元素在涂层中产生分层富集,在界面处发生化学元素扩散,是形成冶金结合的主要机制;Ni,Cr元素在界面形成梯度硬度,涂层中的O元素主要是来源于喷涂过程中的元素氧化和基体中的O元素扩散;涂层中元素扩散机制为非稳态扩散,高温粉末粒子能增加原子扩散层厚度,有利于提高涂层与基体间结合强度。     

Al/Ni/Fe界面扩散反应的实验研究

采用"铆钉法"制备了含有Al/Ni、Al/Fe和Ni/Fe两相界面的扩散偶,以及Al/Ni/Fe多相扩散偶,利用光学显微镜、电子探针分别对每组扩散偶的界面区域进行了观察分析.实验结果显示,固态扩散促使两相界面处生成扩散层,Al/Ni/Fe多层扩散偶中,由于混相层中不同产物的生长速率不同,促使界面不稳定生长,形成束集型的扩散层结构.     

X70/316L复合轧制界面结合性能影响因素研究

采用轧制法对X70管线钢和316L不锈钢进行复合,试验结果显示增大高温阶段轧制道次压下率有助于界面的冶金结合。对复合界面进行微观观察,发现在界面处出现了Cr,Ni的富集及Fe元素的减少,原因在于基板、复板两侧存在较大的浓度梯度,导致在高温下合金元素由高浓度向低浓度扩散;界面处断续分布着Cr,Si,Fe,Ni的氧化物,是造成界面结合强度较低的主要原因。     

2D70耐热铝合金铸态组织研究

利用光学显微镜、扫描电子显微镜、能谱分析、X射线物相分析、透射电子显微镜研究了2D70耐热铝合金半连续铸锭的铸态组织.研究结果表明:2D70耐热铝合金铸态组织为粗大枝晶组织,枝晶间蜂窝状共晶相为AL,A12CuMg/A12Cu,合金中含有大量块状相和条状相,能谱分析显示为含Fe,Ni相,铸态合金中Cu,Fe,Ni元素偏析严重.合金铸态相主要为а(Al),S(Al2CuMg),0(Al2Cu),Al7Cu2Fe,Al7Cu4Ni,Al9FeNi相.     

SnAg0.5CuZn0.1Ni/Cu钎焊接头的界面组织与力学性能研究

通过金相显微镜、X射线衍射仪、透射电子显微镜、扫描电子显微镜和拉力试验机,研究了不同钎焊工艺参数对SnAg0.5CuZn0.1Ni/Cu无铅微焊点界面组织、金属间化合物层厚和力学性能的影响。结果表明,添加0.1%Ni能显著细化SnAg0.5CuZn钎料合金的初生β-Sn相和共晶组织;当钎焊温度为270℃、钎焊时间为240s时,钎焊接头的剪切强度达到最大,为45.6 MPa;钎焊接头界面区粗糙度、金属间化合物层厚度和钎焊接头的剪切强度均随着钎焊工艺参数的变化而变化。     

Effects of Nickel on the Oxide/Metal Interface Morphology and Oxidation Rate During High-Temperature Oxidation of Fe–Cu–Ni Alloys

Steel produced in an electric arc furnace (EAF) contains a high amount of Cu that causes a surface-cracking phenomenon called surface hot shortness. Ni reduces the risk for surface hot shortness, and this work focuses on investigating the following two phenomena caused by Ni during oxidation at 1150 °C for Fe–Cu–Ni alloys: (1) the decrease in oxidation rate and (2) the formation of a wavy liquid-Cu/oxide and of liquid-Cu/γ-iron (γFe) interfaces, which promote Cu occlusion into the scale. Thermogravimetry, scanning electron microscopy, and transmission electron microscopy-energy dispersive spectroscopy techniques were applied. A numerical model also was developed to explain the experimental results. High Ni contents cause higher liquid-Cu/γFe interface nickel concentrations and more potential for an interface breakdown. The decrease in oxidation rate by adding nickel can be explained qualitatively by the decrease in Fe cation transport through the wüstite layer.     

Determination of the Phase Distribution in Sintered TRIP‐Matrix / Mg‐PSZ Composites using EBSD

Metal matrix composites (MMC) containing TRIP‐steel/Mg‐PSZ were processed by cold pressing and conventional sintering in different atmospheres. The MMC was based on austenitic steel in the system Fe‐Cr‐Mn‐Ni showing transformation induced plasticity (TRIP). Depending on the sintering temperature, the sintering atmosphere and the steel composition the phase compositions of MgO partially stabilized zirconia (Mg‐PSZ) were analysed by scanning electron microscopy (SEM), energy dispersive X‐ray microanalysis (EDX) as well as electron backscatter diffraction (EBSD). The interactions between the alloying elements of austenitic stainless steel and the ceramic stabilizer (MgO) as well as the technological parameters lead to a significant change in the phase composition of the Mg‐PSZ. The changes can be analysed by EBSD due to the high spatial resolution.     

Effect of Rare Earth Element Cerium on Mechanical Properties and Morphology of TiN Coating Prepared by Arc Ion Plating

TiN coatings were deposited on polished substrates of W18Cr4V high speed steel by means of vacuum arc ion plating. The effect of cerium on adhesion between TiN coating and substrate was studied. The microstructures and composition of TiN coatings were also investigated by means of scanning electron microscope (SEM), Auger electron spectroscopy (AES), and X-ray diffraction (XRD) technique. It was found that cerium is an effective modifying agent and the addition of suitable amount of cerium to TiN coatings can produce relatively excellent properties such as micro-hardness, wear resistance, oxidation resistance and porosity. The experimental results show that the added cerium in TiN coatings makesa contribution to form the preferred direction along with a (111 ) or (222) close packed face, which may be one of the reasons that improves some properties mentioned above.     

Erratum to: Effects of Nickel on the Oxide/Metal Interface Morphology and Oxidation Rate During High-Temperature Oxidation of Fe–Cu–Ni Alloys

Steel produced in an electric arc furnace (EAF) contains a high amount of Cu that causes a surface-cracking phenomenon called surface hot shortness. Ni reduces the risk for surface hot shortness, and this work focuses on investigating the following two phenomena caused by Ni during oxidation at 1150 °C for Fe–Cu–Ni alloys: (1) the decrease in oxidation rate and (2) the formation of a wavy liquid-Cu/oxide and of liquid-Cu/γ-iron (γFe) interfaces, which promote Cu occlusion into the scale. Thermogravimetry, scanning electron microscopy, and transmission electron microscopy-energy dispersive spectroscopy techniques were applied. A numerical model also was developed to explain the experimental results. High Ni contents cause higher liquid-Cu/γFe interface nickel concentrations and more potential for an interface breakdown. The decrease in oxidation rate by adding nickel can be explained qualitatively by the decrease in Fe cation transport through the wüstite layer.     

不锈钢尘泥球团煤基直接还原动力学

摘要：研究了不锈钢尘泥球团在温度分别为1100、1150、1200、1250℃时的煤基直接还原反应动力学。采用随机成核和随后生长、化学反应控制、相界面反应和n（n=1、2、3、4）维扩散模型及其相应动力学机制函数对反应过程进行拟合,并结合X-射线衍射（XRD）、扫描电镜（SEM）、能谱分析（EDS）等手段对不锈钢尘泥球团煤基直接还原过程的物相组成、显微结构及元素分布进行表征和分析。研究结果表明：反应初期铁氧化物还原速率较快,随后逐渐减慢,当反应至40min后,反应趋向于平衡。在1100~1250℃温度范围内反应遵从随机成核和随后生长及A1(α)=-ln(1-α)机制函数,碳的气化反应和界面化学反应是尘泥球团煤基直接还原反应的限制性环节,该反应活化能E为47.423kJ/mol,线性相关系数为0996。     

Light‐weight steels based on iron‐aluminium ‐ influence of micro alloying elements (B,Ti, Nb) on microstructures,textures and mechanical properties

The influence of the micro alloying elements B, Ti and Nb on the recrystallization texture and mechanical properties of iron aluminium light‐weight steels, particularly with reference to their improved deep drawing properties was investigated. Depending on the combination of the alloying elements the microstructures of the investigated micro alloyed Fe‐6Al steels are influenced by grain refinement. Likewise, variable combinations of micro alloying elements differently affect the texture. Generally, the mechanical properties are improved. However, small amounts of B, Ti and Nb cause superior deep drawing and stretch forming properties of these iron aluminium light‐weight steels The microstructures of various micro alloyed cold rolled Fe‐6Al steel sheets were evaluated by optical microscopy, scanning electron microscopy (SEM) inclusively EDAX and X‐ray diffraction. Texture measurements were performed using a goniometer with a closed Eulerian cradle and analysed by ODF calculations. Tensile tests were carried out at room temperature and 200 °C, respectively. The deep drawing behaviour was determined by performing cupping tests and digitalised strain analysis.     

Influence of Surface Gas-Phase Rare Earth Permeation Plus Laser Melting Solidification on Microstructure and Corrosion Resistance of Pure Iron

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Interfacial reactions in molten Sn/Cu and molten In/Cu couples

The interfacial reactions of molten Sn and molten In with solid Cu substrate were determined by studying their reaction couples. The annealing temperature was 300 °C. The phases formed at the interface were examined by optical microscopy, scanning electron microscopy, and electron probe microscopy analysis (EPMA). The thickness of the reaction layers was measured using an image analyzer. For Cu/Sn couples, two phases, ε and η, were found. Only the Cu₁₁In₉ phase was observed at the interface of the Cu/In couples. In comparison with the results of couples of solid Sn and solid In with solid Cu substrate, their phase formation sequences were similar; however, the interfacial morphology and the reaction rates were different. For the liquid/solid couples, the reaction rate was much faster and the interface was nonplanar. A mathematic model was also proposed to describe the dissolution of the Cu substrate and the growth of the intermetallic compounds. Fast dissolution of the substrate was observed in the beginning of the reaction and was followed by a relatively slow growth of the intermetallic compounds at the interface.     

Microstructure and Interfacial Reactions During Active Metal Brazing of Stainless Steel to Titanium

Microstructural evolution and interfacial reactions during active metal vacuum brazing of Ti (grade-2) and stainless steel (SS 304L) using a Ag-based alloy containing Cu, Ti, and Al was investigated. A Ni-depleted solid solution layer and a discontinuous layer of (Ni,Fe)₂TiAl intermetallic compound formed on the SS surface and adjacent to the SS-braze alloy interface, respectively. Three parallel contiguous layers of intermetallic compounds, CuTi, AgTi, and (Ag,Cu)Ti₂, formed at the Ti-braze alloy interface. The diffusion path for the reaction at this interface was established. Transmission electron microscopy revealed formation of nanocrystals of Ag-Cu alloy of size ranging between 20 and 30 nm in the unreacted braze alloy layer. The interdiffusion zone of β-Ti(Ag,Cu) solid solution, formed on the Ti side of the joint, showed eutectoid decomposition to lamellar colonies of α-Ti and internally twinned (Cu,Ag)Ti₂ intermetallic phase, with an orientation relationship between the two. Bend tests indicated that the failure in the joints occurred by formation and propagation of the crack mostly along the Ti-braze alloy interface, through the (Ag,Cu)Ti₂ phase layer.     

Influence of adding various rare earths on microstructures and corrosion resistance of chromizing coatings prepared via pack cementation on P110 steel

In order to improve the corrosion resistance and increase the service lifetime of P110 steel during operation,four chromizing coatings were formed onto its surface with/without addition of rare earths via pack cementation process.The surface morphologies and microstructures of the chromizing coatings were observed using scanning electron microscopy(SEM),and the phase constitutions were investigated by X-ray diffraction(XRD).Electrochemical corrosion behavior of the chromizing coatings in simulated oilfield ...