钛合金表面激光熔覆钴基复合涂层的组织和性能

利用横流CO2激光器在钛合金表面制备出原位自生TiB体系陶瓷颗粒增强Co基复合材料涂层,以改善常规材料表面综合使用性能。采用XRD、SEM、EPMA等手段对复合涂层进行研究。结果表明：涂层中原位合成的TiB2和TiB陶瓷相均匀分布在γ-Co基合金涂层中。涂层内枝晶组织细小均匀,枝晶内和枝晶间存在明显的组织和成分差异。涂层显微硬度比基体显著提高,约为基体的3倍,同时耐磨性也得到显著改善     

TiB2对Ni基合金激光熔覆层组织与性能的影响

采用5 kW CO2激光器在低碳钢表面熔覆Ni基合金层及TiB2/Ni基合金金属陶瓷涂层,研究了两种涂层的组织、显微硬度以及滑动磨损特性.结果表明,Ni基合金层主要组成相为γ-(Ni,Fe),Cr23C6等,TiB2/Ni基合金复合涂层组成相主要有γ-(Ni,Fe),Ni3B,TiB2和TiC等;Ni基合金层由发达γ-(Ni,Fe)枝晶和其间共晶组织所组成,TiB2/Ni基合金复合涂层典型组织为等轴固溶体以及其间细小共晶组织;TiB2对熔覆层的组织有显著的影响,使熔覆层组织细化,并由树枝晶转变为等轴晶;加入TiB2可显著提高Ni基合金涂层的显微硬度及耐磨性能.     

激光熔覆原位析出增强颗粒热力学及显微组织研究

把理论与试验相结合,通过热力学理论计算,选择出合理的激光熔覆涂层体系,利用横流CO2激光器在铜合金表面激光熔覆Ni基复合材料涂层,原位自生陶瓷颗粒增强相.通过对激光熔覆涂层反应体系△GT的计算及XRD分析得知:TiB增强颗粒可以原位生成.利用OM、SEM和显微硬度计,分析测定涂层的显微组织形貌和截面显微硬度分布情况.结果表明:熔覆层与基体具有良好的结合界面,涂层内枝晶组织细小均匀.熔覆层平均显微硬度比基体显著提高,约为基体平均硬度值的3倍.     

钛合金表面等离子弧熔覆原位自生镍基耐磨涂层的制备及微观结构表征

目的 在钛合金表面制备陶瓷相增强复合耐磨涂层。方法 采用等离子弧熔覆技术,在Ti6Al4V钛合金表面制备了原位自生TiB2、TiC、CrB陶瓷相增强镍基耐磨涂层。采用X射线衍射仪、扫描电镜、能谱仪检测了涂层的物相组成、组织组织以及微区化学成分,采用显微硬度计测试了涂层的硬度。结果 涂层靠近熔合线区域由Ni-Ti树枝晶及枝晶间的共晶组成,在涂层的中上部,大量原位增强相分布于镍基固溶体基体之中。在熔覆过程中,钛合金基材中的Ti元素同熔覆粉末中的B、C元素发生原位冶金反应形成TiB2、TiC增强相,CrB增强相为Ni基熔覆粉末中Cr、B元素反应形成,增强相的形态由各自的晶体结构及熔池凝固热力学与动力学条件决定。涂层的显微硬度得到显著提高,最高达1037HV0.2。结论 采用等离子弧熔覆技术,利用熔池内Ni-Cr-Ti-B-C合金体系的原位冶金反应,可以在钛合金表面制备原位自生TiB2、TiC、CrB增强镍基复合耐磨涂层。同Ti6Al4V基材相比,由于涂层具有大量增强相分布于镍基固溶体的组织特征,其显微硬度得到了显著提高。     

原位合成NiTi-TiB_2复合材料的显微组织与性能

采用电弧熔炼Ti、Ni和B的方法,原位合成B含量不同的3种NiTi-TiB2复合材料,对复合材料的显微组织、成分及压缩力学性能进行研究。结果表明:材料中NiTi与TiB2之间为冶金结合,结合界面致密无孔隙,克服了以往研究中非原位复合材料常见的界面结合差以及致密度低等缺点。当B的摩尔分数超过6%以后,组织中出现粗大的Ti2Ni脆性枝晶,并伴随材料压缩性能的降低。样品力学性能的恶化与粗大TiB2陶瓷以及Ti2Ni脆性枝晶的形成有关。     

Ni60对AlCoCuFeMnNi高熵合金涂层的影响

采用等离子熔覆技术,在Q235钢基体上制备了添加Ni60合金的AlCoCuFeMnNi高熵合金涂层。利用XRD,SEM和EDS研究了涂层的显微组织和相组成,并测试了其显微硬度。结果表明,合金涂层主要由BCC枝晶和FCC枝晶间组织构成,添加Ni60后枝晶间还生成了长条状的Cr_7C_3相,枝晶内的Cr_7C_3相为颗粒状。添加Ni60后涂层硬度最大值达到690 HV0.2,明显高于未添加Ni60涂层的370 HV0.2,涂层硬度提高的主要原因是添加Ni60后涂层中生成了硬质相Cr_7C_3。     

氩弧反应熔覆TiC／Ni复合涂层的组织与性能研究

利用氩弧熔覆技术，以Ni60自熔合金粉、钛粉和石墨粉为原料，在45#钢表面原位反应合成了以TiC颗粒为增强相的Ni基复合涂层。利用金相、SEM、XRD等技术分析了涂层的显微组织，利用显微硬度仪测试了熔覆层显微硬度，用自制磨损试验机对比了熔覆层与淬火回火65Mn钢的耐磨性。结果表明，熔覆层成形良好，无裂纹、气孔等缺陷，与基体呈冶金结合；熔覆层的组织为γ—Ni奥氏体枝晶、CrB、TiB2、Cr23C6、Fe23C6及反应合成的弥散分布的球状TiC陶瓷颗粒；熔覆层显微硬度呈梯度分布，且越靠近基体表面，硬度越低；熔覆层具有优良的耐磨性能。     

氩弧反应熔覆TiC/Ni复合涂层的组织与性能研究

利用氩弧熔覆技术,以Ni60自熔合金粉、钛粉和石墨粉为原料,在45增强相的Ni基复合涂层.利用金相、SEM、XRD等技术分析了涂层的显微组织,利用显微硬度仪测试了熔覆层显微硬度,用自制磨损试验机对比了熔覆层与淬火回火65Mn钢的耐磨性.结果表明,熔覆层成形良好,无裂纹、气孔等缺陷,与基体呈冶金结合;熔覆层的组织为γ-Ni奥氏体枝晶、CrB、TiB2、Cr23C6、Fe23C6及反应合成的弥散分布的球状TiC陶瓷颗粒;熔覆层显微硬度呈梯度分布,且越靠近基体表面,硬度越低;熔覆层具有优良的耐磨性能.     

CeO_2对AlCoCuFeMnNi高熵合金涂层组织和硬度的影响

为探究稀土氧化物Ce O_2对高熵合金的影响,采用等离子熔覆技术,在Q235钢基体上制备了添加0%、0.5%、1%和1.5%(质量分数)Ce O_2的Al Co Cu Fe Mn Ni高熵合金涂层。利用SEM、EDS和XRD研究了Ce O_2对合金涂层组织和硬度的影响。结果表明:涂层组织呈枝晶成长特性,由BCC枝晶和FCC枝晶间组织构成。Ce O_2添加量越多,涂层组织越致密,晶粒越细小,细晶强化是涂层硬度提高的主要原因。     

高速电弧喷涂Fe-TiB2/Al2O3复合涂层的组织及性能

采用低碳钢包覆0～70%TiB2/Al2O3硬质相的粉芯丝材和高速电弧喷涂(HVAS)原位合成MMC涂层,分析和测试了涂层的组织、相组成及耐磨粒磨损性能.结果表明:涂层的性能由其组织和相组成决定,HVAS的非平衡制造过程在涂层中形成多种相:在Fe基固溶体上存在TiB2、Al2O3、FexB及少量的金属间化合物AlFe3和NiAl;随着TiB2及Al2O3在涂层中体积分数的增加,涂层的耐磨粒磨损性能明显提高,磨损质量损失随陶瓷相体积分数的增加呈线性减少;添加合金元素Ni和Al可降低孔隙率,增加涂层耐磨性.使用HVAS方法制备了含TiB2的高性能耐磨复合陶瓷涂层.     

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.