工艺条件对直流磁控溅射沉积ITO薄膜光电特性的影响

研究了采用直流磁控溅射法制备ITO透明导电膜时温度、靶材、氧压比、溅射气压、溅射速率等工艺条件对ITO膜电阻率和可见光透过率等光电特性的影响。实验结果表明,用ITO陶瓷靶溅射镀膜要比In-Sn合金靶好,特别是在电阻率上,前者要低一个数量级左右;并由实验结果得到,当温度330℃,氧氩比1/40,溅射气压0.45 Pa和溅射速率23 nm.min-1左右时,可获得薄膜电阻率1.8×10-4Ω.cm,可见光透过率80%以上的最佳光电特性参数。     

TC4钛合金表面磁控溅射TiAlN涂层的组织与性能

采用TiAl合金靶材,在TC4钛合金基材表面以不同磁控溅射工艺沉积制备了TiAlN涂层。利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)分别分析了不同工艺制备的TiAlN涂层的表面形貌、表面成分及相结构,并对TiAlN涂层的耐蚀性、耐磨性等进行了研究。结果表明,采用磁控溅射工艺可在TC4钛合金表面制备出表面相对平整且结构致密的TiAlN涂层;沉积了TiAlN涂层的TC4钛合金试样的表面性能得到了提高,其磨损失重量和TC4钛合金基材相比降低了80%,耐盐雾腐蚀性能达到了保护级9级。     

Structure and Properties of TiN–Pb Composite Coatings Deposited on VT6 Alloy Magneton Sputtering DC

Russian Journal of Non-Ferrous Metals - Using the reactive DC magnetron sputtering of two separate single-element Ti and Pb targets, a TiN–Pb composite coating was deposited onto a substrate...     

Microstructural and Mechanical Properties Investigation of TiC Reinforced Hardface Alloy Deposited on Mild Steel Substrate

Wear is one of the major problems faced in industry that reduces the life of industrial components and increases the operating costs. Therefore, hardfacing is widely employed by engineers to minimize components’ wear, in which single or multiple layers of hard material that mainly consists of carbides deposited on the base metal. However, these carbide-based materials suffer from solidification cracking due to lack of ductility. In this study, titanium carbide (TiC) reinforced alloy steel deposited using self-shielded flux cored arc welding technique. The microstructure and phase analysis in the hardfaced deposit by scanning electron microscope, energy dispersive x-ray and X-ray diffractometer revealed that the microstructure consists of finely distributed TiC within matrix of martensite and some retained austenite. Microhardness test and pin-on-disk wear test had shown that the clad deposit posses better hardness and wear resistance. Retained austenite formation and TiC precipitation were discussed in detail and correlated with the mechanical properties.     

等离子喷涂高温润滑涂层的组织与力学性能研究

选取了具有优异的高温性能和一定的自润滑性能的高温镍基合金作为复合涂层基体材料,润滑相则分别从高、中、低温固体润滑剂中选取了Ag、CaF2、石墨（C）、MoS、BN为基本润滑组元;耐磨相则选用了在高温下具有良好的抗氧化性能及耐磨损性能的碳化铬（Cr3C2）硬质粒子,采用等离子喷涂技术制备了具有极佳相容性的高温润滑涂层。涂层的结合强度测定、硬度测定和扫描电镜分析均显示出涂层的梯度结构优于单层结构。梯度结构缓和了涂层内部的物理性能差异,不仪使涂层的硬度得到平缓过渡,而且使涂层的结合强度大大提高。有效改善了涂层的性能。     

Effect of Pulsed Magnetic Field on Microstructure and Mechanical Properties of Eutectic Al-Si Alloy

Pulsed magnetic field (PMF) processing has been employed for refining the microstructure of eutectic (Al-12.4Si) Al-Si alloy in the current study. The effect of PMF on microstructure and mechanical properties of eutectic Al-Si alloy was studied. The results show that the morphology of primary α-Al was refined from coarse columnar dendrites to fine equiaxed dendrites by PMF treatment. Fine short rod-like or rounded particle-like eutectic silicon was formed during solidification of eutectic Al-Si alloy treated by PMF. PMF treatment reduced the size of eutectic silicon from 49 to 2.3 μm in length, and the width from 3.1 to 0.6 μm. The aspect ratio of eutectic silicon was also reduced by PMF treatment from slightly less than 16 to slightly less than 4. The ultimate tensile strength and elongation of eutectic Al-Si alloy with PMF treatment at room temperature were about 201 MPa and 8.8 pct, respectively, which were increased by 47 and 73 pct, respectively, compared with the eutectic Al-Si alloy without PMF treatment.     

Influence of Tempering Time on the Microstructure and Mechanical Properties of AISI M42 High-Speed Steel

AISI M42 high-speed steel is prone to fracture as a result of its brittle martensitic microstructure together with abundant carbides located at the grain boundaries. In this study, a series of property tests including hardness, impact toughness, and wear loss were performed to study the effect of tempering conditions on the mechanical properties of AISI M42 high-speed steel over holding time ranging from 1 to 20 hours. The effects of the tempering time on the characteristics and growth of carbides were also investigated. The results indicated that carbides in the experimental steels were obviously coarsened when the tempering time exceeded 4 hours. The dimension of the carbides increased, while the volume fraction decreased with the increasing tempering time, and the grain sizes were significantly augmented due to the reducing of small carbides. Moreover, the dislocation density decreased with the increasing tempering time, which led to the reducing of the yield stress of high-speed steel. An appropriate holding time (4 hours) resulted in fine-scale secondary carbides and a smaller grain size, which efficiently improved the impact toughness and wear resistance simultaneously. Nevertheless, a prolonged tempering time (>?4 hours) promoted the coarsening and coalescence of carbides, which were detrimental to the impact toughness and wear resistance. Consequently, the formation of fine-scale secondary carbides is the major influential factor to improve both the wear resistance and impact toughness.     

锻造比对H13钢组织和力学性能的影响

 利用金相显微镜及SEM研究了在单向热锻拔长的工艺下,锻造比的不同对H13电炉钢组织和力学性能的影响。结果表明：同一锻造比下H13电炉钢的横向冲击功明显小于纵向,且无论在钢锭的横向、纵向边部到心部的冲击功越来越差;不同的锻造比对横向冲击功影响不大,而随着锻造比的增大纵向冲击功增大。研究表明,单向热锻拔长不能有效地提高钢材横向止裂性能;电炉H13热作模具钢的锻比控制在4~6的范围内较为合适。     

冶炼工艺对H13钢组织和力学性能的影响

 研究了真空感应+电渣重熔、电炉+LF+VD两种特殊钢冶炼工艺对H13钢组织和力学性能的影响,结果表明：真空感应+电渣重熔冶炼对提高H13钢洁净度,降低H13钢中S、P含量,降低合金元素偏析有一定作用,在一定程度上提高了H13钢心部横向冲击韧性,但由于组织中大量一次碳化物的存在,制约着H13钢横向冲击韧性的提升。     

Microstructure and Corrosion Properties of AlCoCrFeNi High Entropy Alloy Coatings Deposited on AISI 1045 Steel by the Electrospark Process

Electrospark deposition (ESD) was employed to clad the AlCoCrFeNi high-entropy alloy (HEA) on AISI 1045 carbon steel. The relationship between the microstructure and corrosion properties of the HEA-coated specimens was studied and compared with that of the copper-molded cast HEA material. Two major microstructural differences were found between the cast HEA material and the HEA coatings. First, the cast material comprises both columnar and equiaxed crystals with a columnar-to-equiaxed transition (CET), whereas the HEA coatings consist of an entirely columnar crystal structure. The CET phenomenon was analyzed based on Hunt’s criterion. Second, unlike the cast HEA material, there was no obvious Cr-rich interdendritic segregation and nano-sized precipitate distributed within the dendrites of the HEA coating. With regard to corrosion properties, the corrosion current of the HEA-coated specimen was significantly lower than for the 1045 steel and the cast HEA material. This was attributed to the ESD specimen having a relatively high Cr oxide and Al oxide content at the surface. Moreover, for the ESD specimen, the absence of Cr-rich interdendritic phase and second-phase precipitation resulted in a relatively uniform corrosion attack, which is different from the severe galvanic corrosion attack that occurred in the cast specimen.     

Influence of Upset Pressure on Microstructure and Mechanical Properties of Friction-Welded AISI 4140 Low Alloy Steel Pipes

Transactions of the Indian Institute of Metals - In the present study, low alloy steel AISI 4140 pipe in reheated, quenched and tempered (RQT) condition was friction-welded using 6.4 MPa...     

Mg对热作模具钢H13组织和力学性能的影响

试验钢的生产流程为2 t中频感应炉-200 kg电渣重熔(Φ180 mm)-退火-镦粗至Φ325 mm-球化退火-1050℃淬火-590℃回火,炉冷。试验研究了0~0.0010%Mg对热作模具钢H13(/%:0.40~0.41C、0.98~1.01Si、0.29Mn、4.95~5.08Cr、1.21~1.22Mo、0.91-0.93V、0.023~0.027P、0.006~0.007S)组织和力学性能的影响。结果表明,随钢中Mg含量由0提高至0.0010%时,试验模具钢H13的平均抗拉强度和HRC硬度值分别从1 617.6 MPa和45.7提高至1 702.9 MPa和47.8;Mg可以增加钢中回火马氏体的稳定性,高温回火后含Mg模具钢H13的组织中出现大量回火屈氏体,而且部分碳化物在Mg-Al夹杂物周围析出,成球形,尺寸小于10μm,有利于改善钢的性能。     

模拟焊后热处理工艺对13MnNiMoR钢板组织和性能的影响

分析模拟焊后热处理工艺对压力容器用高性能13MnNiMoR钢板组织和性能的影响,结果表明:钢板经模拟焊后热处理,抗拉强度降低,Z向性能改善;温度相同,随着保温时间的延长,抗拉强度降低且趋稳,延伸率逐渐降低;时间相同,随着保温温度的升高,屈服强度和Z向值降低;随着温度提高或保温时间延长,晶粒尺寸增大并趋向均匀。试板经过模拟焊后热处理,钢板力学性能满足标准要求。     

Toughening of AISI 410 Stainless Steel Through Quenching and Partitioning and Effect of Prolonged Aging on Microstructure and Mechanical Properties

Metallurgical and Materials Transactions A - AISI 410SS is one of the widely used martensitic steels. Tramp elements present in this steel segregate during tempering at prior austenite grain...     

电渣重熔速度对H13钢组织和冲击性能的影响

利用双极串联电极坯电渣重熔直径φ385mm H13钢锭,研究了快速重熔与慢速重熔对电渣锭的铸态组织、锻造成品的退火组织和冲击性能的影响。结果表明:快速重熔比慢速的电渣锭的二次枝晶间距大,并且一次碳化物等枝晶间显微偏析严重;慢速重熔的锻造成品的退火组织均匀和带状偏析减轻,横向冲击性能明显提高,达到NADCA207-90标准规定的优质H13钢的水平。