45钢低温双辉等离子渗铬的研究

采用"氮化+双辉等离子渗铬"复合工艺,在630℃扩散层组成;渗层表面形成4～5μm的沉积层,含铬量达到52%左右,致密并与基体结合紧密;内有20～25μm的扩散层.扩散层含铬量呈梯度分布;表面物相由Fe-Cr、Cr7C3、Cr23C6、CrN等组成;渗层表面显微硬度达950HV,硬度向内呈梯度分布,而没有改变基体材料的结构和性能.这种高的表面硬度对提高材料表面耐磨性具有重要意义.     

碳素工具钢560℃双辉等离子渗铬硬化的研究

采用离子氮化＋双层辉光离子渗金属的复合处理渗铬新技术，对碳素工具钢进行560℃表面渗镀铬硬化研究。结果表明，渗镀层组织由沉积层＋扩散层组成；渗镀层表面形成4～5μm的沉积层，含铬量达50％以上，致密并与基体冶金结合；内有20-25μm的扩散层，扩散层含铬量呈梯度分布；经X射线衍射分析，其表面物相由Fe-Cr、CrN、Cr7C3、Cr23C6等组成；渗镀层的显微硬度达1000HV以上，硬度向内逐步降低，呈梯度分布。     

T10钢低温双辉等离子渗镀铬硬化的研究

采用双辉等离子渗铬＋离子渗氮的复合工艺,以T10钢为基材在560℃研究了该工艺对渗层硬化效果的影响。结果表明：离子渗氮前渗层表面有3-5μm的沉积层,组织致密并与基体结合紧密,基体组织无明显变化;沉积层含铬量达46%以上,扩散层深15-20μm;渗层表面物相均由Fe、Fe-Cr、Cr7C3、Cr23C6等组成;表面显微硬度达650-850HV,硬度向内呈梯度分布。渗镀层经离子渗氮后的组织与氮化前的组织无明显变化,但表面物相为Fe-Cr、Cr7C3、Cr23C6、CrN、Fe4N,表面显微硬度1000-1350HV,较未渗氮前提高65%以上,表明本复合工艺能有效提高铬渗镀层的显微硬度。     

Ti6Al4V合金与AISI420不锈钢表面离子渗Cr及耐磨性

为了改善钛合金和不锈钢的耐磨性,对Ti6Al4V合金和AISI420马氏体不锈钢表面进行真空辉光离子渗Cr,对比研究了合金化层的组织结构和摩擦磨损性能的相关性.结果表明,两种基材的合金化改性层厚度均达60μm以上,结构致密,结合强度高.Ti6Ai4V合金改性层由Cr沉积层、富Cr2Ti层、CrTi4层和Cr-Ti固溶层组成,其中富Cr2Ti层硬度最高,是基材的2.3倍;AISI420不锈钢渗Cr层由Cr沉积层和扩散层组成,扩散层中富含Cr23C6相,二者过渡区的硬度最高,是基材的4.5倍.表面渗Cr显著提高两种材料的耐磨性,这与渗Cr层的物相结构有关.Ti6Al4V合金的Cr沉积层和富CrTi相层均具有优异的耐磨性,而固溶层的耐磨性较差;AISI420钢基材的Cr沉积层和过渡层均具有优异的耐磨性,而扩散层的耐磨性稍差.渗Cr处理使两种基材的磨损机制均由磨粒磨损为主转化为粘着磨损为主.     

40Cr钢表面电火花沉积WC的界面行为

以WC合金作为电极,氩气为保护气体,采用电火花沉积技术在40Cr钢表面沉积WC合金层,通过显微硬度计、扫描电镜(SEM)及能谱分析(EDS),X射线衍射等测量方法,研究了40Cr钢表面电火花沉积WC层的显微硬度、表面状态、界面行为及相结构组成.结果表明,WC合金电火花沉积层存在微裂纹及气孔,主要由W、Fe6W6C、Fe3C和Cr23C6等相组成;沉积层显微硬度达820 HV,为基体的4.5倍;沉积层断面连续、致密,厚度为30 μm;沉积层与基体之间发生了元素的相互扩散与合金化过程,呈冶金结合,无明显界面.     

γ-TiAl合金表面辉光等离子渗Cr层的组织与性能

利用双层辉光等离子表面渗金属技术(DGPSAT)在γ-Tial合金表面进行等离子渗Cr处理,采用OM、SEM、EDS和XRD分析了渗Cr合金层的显微组织、化学成分及其相组成,并测试了其显微硬度分布和耐磨性.结果表明,γ-TiAl合金经双层辉光等离子渗Cr处理后,其表面形成以Al8Cr5、TiAl、Ti3Al、Cr等相组成的合金层,有效厚度约为35μm,渗层与基体结合牢固;渗Cr层组织成分及其横截面显微硬度由表及里均呈梯度分布;其摩擦磨损性能亦得到提高.     

TA15合金渗Cr和Cr-Si复合渗层的高温摩擦行为研究

通过双层辉光等离子技术在TA15钛合金表面制备了渗Cr层和Cr-Si复合渗层。采用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射(XRD)等手段研究了渗层的微观结构、成分分布及相结构。此外,还测定了渗层与基体金属的结合强度、纳米压痕硬度和弹性模量。结果表明,40μm厚的CrSi复合渗层均匀、致密,且大致可分为三部分;而渗Cr层则由12μm的Cr沉积层和18μm的扩散层组成。Cr-Si复合渗层的硬度和弹性模量分别为16 306 MPa和519 GPa,远大于渗Cr层的6 750MPa和364 GPa。在300℃进行了高温球盘磨损试验,以研究渗层的高温摩擦学行为。结果表明,Cr-Si复合渗层的磨痕比渗Cr层更窄更浅,摩擦因数和比磨损率也更小。     

Ti_2AlNb合金表面等离子渗铝层的摩擦性能

利用双层辉光等离子冶金技术在Ti2Al Nb合金表面制备渗铝层,分析了渗铝层的成分、显微组织及相结构,测定了渗层的硬度分布,评价了室温干滑动磨损条件下的摩擦磨损性能。结果表明:在Ti2Al Nb合金表面形成约4μm的沉积层和6μm合金扩散层。扩散层中的硬度随渗层厚度呈梯度递减。渗铝层的磨损率为0.18×103mg/N·m,仅是基体的0.67倍,磨损机理属于轻微磨损,可见,双辉等离子渗铝在一定程度上提高基体材料的耐磨性。     

γ-TiAl合金表面辉光等离子Ni-Cr共渗层的组织与性能

采用双层辉光等离子表面冶金技术在γ-TiAl合金表面进行Ni-Cr共渗处理,形成均匀致密的Ni-Cr合金层,通过SEM、EDS、XRD等对其渗层显微组织、化学成分和相结构进行分析,并测试了合金层的显微硬度及耐磨性。结果表明,合金层有效渗层厚度为25μm,主要由Cr2 Ti、AlTi、Cr、NiTi2、Cr1.75 Ni0.25 Ti等相组成;合金层中合金元素Cr和Ni由表及里呈梯度分布,合金层与基体结合牢固;合金层的显微硬度、动态硬度及摩擦磨损性能显著高于基体。     

工艺参数对Q235钢辉光等离子渗Cr渗层影响的研究

在不同电源、不同气压、不同温度工艺参数下对Q235钢表面进行辉光等离子渗Cr.用金相显微镜及扫描电镜观察渗层组织形貌,用能谱仪进行渗层Cr元素浓度分布测定,用X衍射仪进行物相分析.结果表明:不同电源渗Cr的渗层均出现反应扩散现象,渗层均为明显的柱状晶组织;脉冲电源渗Cr层厚度最大达到100 μm以上,表面Cr含量达到40%(w%)左右,渗层距表面10μm处Cr含量达到10%以上,渗Cr层成分分布明显好于直流电源和双辉双电源;脉冲电源渗Cr随气压的升高,渗层厚度及Cr含量先增大后减小,工艺条件下最佳气压值为30 Pa;脉冲电源渗Cr随着温度的升高Cr渗层厚度增加,渗层Cr浓度分布曲线随温度的升高由表面向内梯度变得平缓且浓度提高.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.