Effects of Thermal Exposure on the Tensile and Fatigue Properties of Cast Ti—47Al—2Cr—2Nb--0.15B Alloy

测量了铸造Ti—47Al—2Cr—2Nb-0．15B(原子分数，％)合金的高温疲劳强度以及650℃／100h和800℃／100h热暴露后的拉伸性能和疲劳强度，采用X射线衍射和扫描电镜等方法分析了经热暴露后合金基体组织的变化和表面层的结构．随暴露温度的提高，合金的室温塑性和疲劳强度降低，650℃附近有一转折点，大于650℃时上述性能加速下降；合金高温疲劳性能具有相似的变化规律．显微分析表明，在热暴露或高温疲劳实验时，表面形成的脆性层是导致合金性能降低的直接原因；而随温度的提高，表面层由渗氧层转变为氧化层是导致合金性能随温度变化出现转折的原因．     

微合金元素对超低碳钢高温抗氧化性能的影响

采用热重分析仪和Gleeble-3500热模拟试验机研究了Si、Cr、Ni和Cu微合金元素对超低碳钢氧化行为和氧化层的影响。结果表明,在氧化过程中合金元素在氧化层与基体的界面处发生富集,其中Si和Cr形成了一层连续的富集层,Cu和Ni以粒子形式在界面处析出。微合金元素的富集一方面抑制了铁原子由基体向外扩散,从而显著提高钢的抗氧化性,其中Si和Ni的效果最好,Cr次之,Cu的效果最差;另一方面提高了氧化层与基体的结合力,抑制了氧化层的鼓泡现象,Si的抑制效果最好,Cu次之,Cr和Ni的抑制效果最差。     

W，B，Y合金元素对高铌TiAl基合金高温长期抗氧化性能的影响

在高铌TiAl基金属间化合物的基础上添加W，B，Y合金元素，熔炼了5种合金，研究了这5种合金在900℃静止空气中的断续氧化行为。1000h氧化后的结果表明：含0．1％（原子分数，下同）的Y使合金的抗氧化性有所提高，促进合金形成了以Al2O3为主的连续致密氧化层；存高铌含Y合金中添加W，B2种合金元素则导致基体发生了严重的内氧化，使合金的抗氧化性能降低。     

中碳钢盘条的高温氧化行为研究

针对中碳钢盘条的高温氧化问题,利用热重分析仪对45钢和40Cr钢盘条的高温氧化行为进行了试验研究;采用场发射电子探针表征了氧化铁皮厚度及截面微观形貌,对氧化铁皮形貌演变规律以及合金元素在氧化铁皮与基体界面处的分布规律进行了研究分析。结果表明:45钢和40Cr钢盘条的氧化增重曲线在1 050~1 250 ℃范围内遵循抛物线规律,当氧化条件相同时,相比于常规低碳钢,其氧化激活能较高,抗氧化性能更好;氧化铁皮呈典型的3层结构,从外到里分别为Fe₂O₃、Fe₃O₄及FeO,并且在氧化铁皮与基体界面处存在合金元素富集层;45钢盘条在高温氧化时,Cr元素分布不明显,Si元素在氧化铁皮与基体界面处有少量富集,Mn元素在氧化铁皮中均匀分布;40Cr钢盘条在氧化铁皮与基体界面处不仅有富Si层,还明显存在一层均匀完整的富Cr层,由于合金元素富集层阻碍了Fe²⁺向外扩散,提高了盘条的高温抗氧化性能。     

NiCrdMoNb合金化层对TiAl金属间化合物抗氧化性能的影响

探讨了利用双层辉光等离子渗金属技术（GDPSAT）溅射NiCrMoNb合金化层对TiAl金属间化合物静止空气中高温氧化抗力的影响，结果表明，不处理的TiAl由于TiO2为主的氧化层的剥落抗氧化性能较差，而TiAl-NiCrMoNb合金层由于形成了致密，晶粒细小的富Al2O3层而使TiAl抗氧化性能大大提高，合金层与基体之间存在互扩散，Ni,Cr，Mo,Nb的界面富集导致界面化学性质的很大改变。     

硅和铬元素对22MnB5热冲压钢氧化膜形成的影响

为明确合金成分对22MnB5热冲压钢氧化膜的作用机制，采用差热分析仪、场发射扫描电镜和电子探针等分析了试验钢的氧化增重特性、界面元素富集情况、氧化膜表面及截面特征，系统研究了Si、Cr元素对氧化膜形成、起泡和冲压粉化行为的影响规律。结果表明：在1 100℃以下温度范围内，添加Si、Cr元素有利于提高试验钢的抗氧化性；Si元素在试验钢氧化膜/基体界面富集后形成Fe₂SiO₄,可降低界面原子错配度，有效减少界面力，抑制氧化膜的脱落；Cr元素在试验钢基体表面形成富Cr层，阻碍Fe²⁺和O^2-交互扩散，提高了试验钢基体的抗氧化能力；但试验钢在单独添加Si元素条件下易于出现明显的晶间氧化情况。同时添加Si和Cr元素后，22MnB5钢的氧化膜冷弯粉化率明显降低，可有效避免热冲压过程氧化膜粉化问题。     

电泳共沉积NiCoCrAlY粘结层制备及抗高温氧化研究

目的 分析研究Ni基合金与粘结层之间的扩散和界面反应规律,以及其对热障涂层的抗高温氧化性能和工作寿命的影响.方法 采用电泳共沉积、真空致密化处理,在K17镍基高温合金表面制备NiCoCrAlY粘结涂层,并进行1000℃×100 h抗高温氧化实验,采用XRD、SEM、EDS分析NiCoCrAlY粘结涂层在高温氧化过程中合金元素的扩散规律.结果 高温氧化动力学曲线表明,氧化100 h制备的NiCoCrAlY粘结涂层的氧化速率为17.2134 mg/cm2,远低于K17镍基高温合金的.Ni由涂层向基体内扩散,Cr和Co向外扩散,Al向界面处扩散.电泳沉积制备的NiCoCrAlY粘结层经真空致密化处理后,涂层均匀、致密,粘结层主要由Ni3 Al、Al3 Y5 O12、Cr23 C6以及α-Al2 O3等组成.结论 NiCoCrAlY粘结涂层的抗高温氧化性高于K17镍基高温合金,在高温氧化过程中,α-Al2 O3氧化膜提高了NiCoCrAlY粘结涂层的高温抗氧化性.Ti主要来自基体的缺陷中,随着高温氧化作用,获得了由基体向外扩散所需要的能量,并且同时与氧反应生成TiO,TiO容易在粘结层表面形成泡状物质,Ti的扩散对粘结层的致密度与均匀度造成一定的影响.     

铁素体不锈钢室温熔盐镀铝层的热处理

以1Cr17铁素体不锈钢为基体,在摩尔比2∶1的酸性AlCl3-EMIC(1-甲基-3-乙基咪唑氯化物)室温熔盐中电沉积均匀致密的铝镀层,然后分别在300℃、650℃6、70℃下进行不同时间的热处理,用刻划撕扯法判断镀层的结合力,用SEM、EDS及XRD对热处理后的试样界面进行微观分析。结果表明,试样经热处理后,结合力有了很大提高,镀层与基体之间发生互扩散形成合金层,合金层由含Cr的Fe2Al5、FeAl、Fe3Al等相组成,且随着温度提高及热处理时间的增长,镀层由Fe2Al5相进一步转变成铁含量高、韧性高的FeAl、Fe3Al相。     

La0．5Sr0．5CoO3涂层对Fe-13Cr合金的电导及组织的影响

制备了高电导的La0．5Sr0.5CoO3块样，其800℃电导率为238S／cm。通过磁控溅射将La0.5Sr0．5CoO3涂覆在Fe-13Cr合金表面，再进行800℃等温氧化100h。SEM分析发现，Fe-13Cr基体中的Cr和Mn向涂层表面外扩散，同时涂层中的La，Sr及Co原子向合金基体内部扩散。电阻测试发现，氧化过程中，形成的反应层并没有显著降低试样的面电阻，800℃等温氧化100h后的面电阻为6mΩ·cm^2。     

Al、Si及Y多元合金化对Cr-20Nb合金高温氧化行为的影响

针对软第二相Cr稍微降低Laves相NbCr2合金的1200℃抗氧化性,采用Al、Si及Y多元合金化来提高Cr-20Nb合金的高温抗氧化性能。结果表明,多元合金化的Cr-20Nb合金1100℃及1200℃抗氧化性均好于加入单一合金化的及纯Cr-20Nb合金,并随着Si合金元素含量增加,Cr-20Nb合金的氧化增重变小,抗氧化性变好;SEM结果表明,添加合金元素后,氧化膜与基体的粘附性得到了明显提高。     

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.