半固态A356铝合金浆料的行波搅拌制备工艺

采用行波电磁搅拌和低过热度浇注复合制备工艺,成功制备出初生α-Al为球状的较大尺寸A356铝合金半固态浆料.研究了浇注温度、搅拌频率和搅拌功率对A356铝合金半固态浆料组织的影响.结果表明,随着浇注温度的降低,半固态A356铝合金组织中的初生α-Al更圆整.当搅拌频率达到或高于10Hz时,半固态A356铝合金浆料中的组织比较理想.当电磁搅拌功率增大时,半固态A356铝合金熔体中的蔷薇状初生α-Al受到更剧烈的附加温度起伏而使枝晶根部熔断,形成更多更圆整的球状初生相.因此,在630℃浇注、搅拌频率为10Hz和搅拌功率为1.72kW下,能制备出更圆整、细小的初生α-Al.     

蛇形通道浇注法制备半固态ZL101铝合金浆料

采用蛇形通道浇注法制备半固态ZL101铝合金浆料,研究了浇注温度、弯道数量、冷却方式对半固态浆料组织的影响。结果表明,浇注温度在640~680℃范围时可获得理想的半固态ZL101铝合金浆料,其组织随浇注温度的降低,由蔷薇状向近球状或球状组织演变。在相同浇注温度下,弯道数量增加,可以改善初生α-Al晶粒的形貌,降低晶粒尺寸。弯道内的合金熔体具有"自搅拌"作用,使初生晶核演变为球状或近球状晶粒。     

蛇形通道法制备ZL101铝合金半固态浆料（英文）

采用蛇形通道法制备ZL101铝合金半固态浆料,研究浇注温度、弯道数量、蛇形通道温度对ZL101铝合金半固态浆料显微组织的影响。结果表明:浇注温度在630~680°C范围时可获得满意的ZL101铝合金半固态浆料,随浇注温度的降低,初生α(Al)由蔷薇状向近球状或球状组织演变。在相同浇注温度下,弯道数量增加,可以改善初生α(Al)晶粒的形貌,降低晶粒尺寸。当蛇形通道温度提高时,通过降低浇注温度,同样可以获得合格的半固态浆料。弯道内的合金熔体具有"自搅拌"作用,使初生晶核演变为球状或近球状晶粒。     

蛇形通道浇注制备半固态浆料组织的演化

采用蛇形通道浇注制备7075铝合金半固态浆料,研究了不同浇注温度下浆料组织中初生α-Al的形貌演变,通过残留在蛇形通道内部的凝固壳分析了蛇形通道内部合金熔体的形核动力学条件,自由晶的形成、长大与球化机理。结果表明:自由晶的数目决定了初生α-Al的形态,随着浇注温度降低,过冷度的增大,浆料组织中的初生α-Al的形貌由蔷薇状向近球状转变,晶粒尺寸逐渐变小,晶粒数目增多;蛇形通道内过冷的合金熔体经过弯道的作用,熔体内部的对流、剪切和"搅拌"使初生激冷α-Al晶核经过游离、增殖、长大和熟化,最后演变成近球状和蔷薇状的α-Al晶粒;球状初生α-Al晶粒的演变机制主要为枝晶抑制生长机制,也包括枝晶臂根部熔断机制。     

6061铝合金半固态浆料的行波电磁搅拌制备工艺

采用低过热度浇注和弱行波电磁搅拌工艺,成功制备出6061铝合金半固态浆料。研究了浇注温度、搅拌功率和搅拌时间对6061铝合金半固态浆料的影响。结果表明:低过热度浇注和弱行波电磁搅拌技术可获得具有良好球状初生α-Al的6061合金半固态组织。浇注温度接近液相线温度,搅拌功率大于2.5kW,搅拌时间大于10s时,6061铝合金半固态浆料中的初生α-Al细小圆整,尺寸均匀。但是当浇注温度降至液相线温度时,组织中出现少量树枝晶。最佳工艺参数:浇注温度667℃、搅拌功率2.5kW、搅拌时间10s。     

行波电磁搅拌制备半固态AlSi7Mg合金浆料

采用低过热度浇注和弱行波电磁搅拌复合制备工艺制备较大容量的半固态AlSi7Mg合金浆料,探讨了电磁搅拌功率和频率对较大容量半固态AlSi7Mg合金浆料组织中的初生α-Al形貌和分布的影响规律。试验结果表明,在低过热度浇注和弱行波电磁搅拌条件下,当浇注温度为630℃、搅拌功率为1.52kW、电磁搅拌频率为5Hz、搅拌时间为8s时,可制备出初生α-Al形貌呈小而圆整的球状晶粒、组织分布均匀、较大容量的半固态AlSi7Mg合金浆料。在低过热度浇注和弱行波电磁搅拌条件下,当浇注温度为630℃、电磁搅拌频率为5Hz,,适当提高电磁搅拌功率可改善初生a-Al的形貌,组织分布比较均匀,但当搅拌功率超过1.52kW时,初生α-Al形貌并没有得到进一步的改善,初生α-Al形貌大部分为球状,组织分布也比较均匀。在低过热度浇注和弱行波电磁搅拌条件下,当浇注温度为630℃、电磁搅拌功率为1.27kW,适当提高电磁搅拌频率可改善初生α-Al的形貌,但当电磁搅拌频率超过10Hz时,初生α-Al形貌并没有得到明显改善,初生α-Al形貌大部分以球状为主,组织分布比较均匀。     

弱搅拌功率对半固态AlSi7Mg合金浆料组织的影响

采用低过热度浇注和弱电磁搅拌制备浆料技术制备半固态AlSi7Mg合金浆料,研究了弱搅拌功率对合金浆料初生相α-Al形貌的影响以及浆料组织的径向分布.研究结果表明, 在低过热度浇注和弱电磁搅拌条件下,当AlSi7Mg合金液在浇注温度为630 ℃、搅拌功率为0.36 kW时可制备出初生α-Al相形貌呈小而圆整的球状晶粒、组织分布均匀、直径为127 mm的AlSi7Mg合金浆料;在低过热度浇注和弱电磁搅拌条件下,适当提高搅拌功率可改善初生α-Al相形貌,但当搅拌功率提高到一定程度,再增大搅拌功率,初生α-Al相形貌并没有得到进一步改善;从半固态AlSi7Mg合金浆料组织的径向分布看,由边部到心部,浆料的组织形貌从枝晶组织向蔷薇状组织再向球状组织演化.     

采用蛇形管通道浇注法制备半固态浆料

采用蛇形管浇注法制备了半固态A356铝合金浆料.结果表明:当浇注温度为660～680 ℃时,采用蛇形管可以制备出半固态A356铝合金组织,且管道内没有出现凝固壳;蛇形管通道的直管段长度对半固态浆料组织有较大影响,即直管段长度变短后,浆料组织变差,且制备合适半固态浆料组织的浇注温度也降低;沿径向浆料组织的形貌分布不同,由心部的球状初生α相向过渡区域的球状和蔷薇状初生α相的混合组织转变,边缘部位为蔷薇状的初生α相组织.     

半固态A356合金浆料的新型制备技术

采用直管浇注法制备了半固态A356铝合金浆料,获得了金属半固态加工要求的细小、球状的“非枝晶”组织,并分析了浇注高度和浇注温度对组织形成过程的影响。实验结果表明：直管在该工艺中起到了增加形核的作用;合适的浇注高度和低温浇注有利于形核;随着浇注高度的提高,初生-αAl晶粒逐渐从蔷薇状向球状和颗粒状转变,晶粒形貌也逐渐变好;随着浇注温度的降低,初生-αAl晶粒向球状或颗粒状转变,分布均匀,圆整度好。在本实验条件下,最佳的浇注高度为430 mm;合适的浇注温度为630～615℃。所得浆料从中心到边缘经历了一个从球状向破碎蔷薇状、再向枝晶状组织转变的过程。     

半固态A356铝合金浆料的LSPWES制备和流变成形

利用短时弱电磁搅拌和低过热度浇注(LSPWES)制备了半固态AlSi7Mg铝合金浆料,随后对该浆料进行了均热处理,并探讨了压射比压对铝合金浆料流变挤压铸造过程的影响。制备结果表明:在630~650℃下浇注,同时附以短时低强度电磁搅拌,AlSi7Mg合金中的初生α-Al呈现为球状,个别的初生α-Al呈现为蔷薇状;在固液两相区进行均热处理时,促进了初生α-Al的熟化作用,使初生α-Al进一步球化和粗化。压射比压对半固态AlSi7Mg合金浆料的充填性影响较大,压射比压越高,型腔越容易充满;对于本试验条件,只要压射比压≥34MPa,半固态AlSi7Mg合金浆料都可充满型腔。流变挤压铸件的组织分布很均匀,表明采用低过热度浇注和弱电磁搅拌相结合所制备的半固态AlSi7Mg铝合金浆料适合流变挤压成形,有利于获得高质量的压铸件。     

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.