Sc、Zr微合金化对Al-4Cu-1.5Mg合金组织与性能的影响

试验研究了Sc和Zr复合微合金化对Al-4Cu-1.5Mg合金铸态显微组织与力学性能的影响规律。结果表明,复合添加微量Sc和Zr,有效改善了合金铸态微观组织,细化了合金晶粒,使粗大的树枝晶转变为均匀细小的等轴晶。当Sc、Zr含量分别为0.4%和0.2%时,合金的抗拉强度、屈服强度及伸长率分别为275.0MPa、176.0MPa和8.0%,与未添加合金元素的Al-4Cu-1.5Mg合金相比,抗拉强度提高了55.3%,伸长率提高了近3倍。     

合金元素对ER5356铝合金铸锭组织性能的影响

铝合金焊丝质量很大程度上取决于铝合金原材料质量,即用于制备焊丝的铝合金锭坯的质量。采用OM,SEM,EDS等方法,研究了模铸ER5356铝合金中Mg,Cr,Ti元素的强化机制以及Fe,Si杂质元素的影响机理以及均匀化热处理工艺。结果表明,Mg元素在晶界可形成连续网格状分布Al8Mg5相,该相在晶内则以弥散点状形态分布;Cr元素则在晶界和晶内均可形成固溶有Ti元素的块条状θ(Cr Al7)相,以上两相均起到析出强化的作用;试验并未发现明显β(Ti Al3)相,Ti元素在该合金中主要起细化晶粒的作用;Fe元素主要出现在晶内第二相周围α-Al基体中,并未发现Fe,Si脆性杂质难溶相,说明目前熔炼净化浇注工艺可以保证合金中不出现明显的杂质相以影响ER5356铝合金的组织和性能。合理的均匀化热处理可以有效地消除合金元素Mg的微观偏析,使富集在晶界上的Al8Mg5相以及晶内其他第二相大部分回溶,应力得到释放。     

5356铝合金半连续铸锭显微组织及力学性能

采用半连续铸造工艺成功制得质量合格的5356铝合金铸锭,并通过金相显微镜、扫描电镜、透射电镜、力学性能测试等手段,对均匀化退火前后铸锭的显微组织及力学性能进行了分析。结果表明,5356铝合金铸态组织主要由α-Al+β-Al3Mg2+其他杂质相组成;Al3Mg2相除沿晶界呈网状分布外,还会以颗粒状在晶内析出;大块相呈不规则多边形,数量较少,主要化学成分为Al、Mg、Ti、Cr;小块相呈鱼骨状,数量相对较多,主要成分为Al、Mg、Fe、Mn;5356铝合金铸锭经均匀化退火后抗拉强度达到315.9 N/mm2,断后伸长率达到30.7%,比均匀化前分别提高了10.4%和27.4%。     

微量Sc对2A14铝合金轮毂组织与性能的影响

采用铸锭冶金及等温复合锻造方法,制备了含Sc的2A14铝合金轮毂锻坯,研究了Sc对锻坯组织与性能的影响。结果表明,Sc含量提高至0.3%时,2A14铝合金的晶粒得到明显的细化,大部分晶粒呈等轴晶状态。添加Sc提高了2A14铝合金的伸长率,但其抗拉强度明显降低,使其低于400MPa,原因在于添加Sc后,大量消耗2A14铝合金中的Cu元素,导致强化相θ′-Al2Cu体积分数减少。但Sc能有效抑制合金中的再结晶,减小轮毂锻坯各部位的性能差异,并提高合金的耐热性能。     

微量钪对Al-3%Cu合金组织与性能的影响

采用硬度、拉伸性能测试、金相组织观察、扫描电镜与能谱分析以及X-射线衍射等方法，研究了微量稀土元素Sc对Al-3％Cu合金组织与性能的影响。结果表明，稀土元素Sc能够强烈地细化Al-Cu合金的晶粒，改善枝晶网胞。微量Sc元素添加到Al-3％Cu合金中，合金的抗拉强度σb和屈服强度σ0．2均有所提高(△σ约为30MPa)，对合金的伸长率几乎没有影响；微量Sc元素添加到Al-3％Cu合金中，除部分固溶于Al基体中外，大部分与Al形成对合金起强化作用的Al3Sc共格相，对合金起强化作用，没有发现其他相，包括W(AlCuSc)相生成。     

Mg对真空-氩气熔炼铸造5356铝合金组织和性能的影响

采用真空-氩气熔炼铸造制备了不同Mg含量的5356铝合金,研究了真空熔炼对铝合金熔体的净化作用,分析了不同Mg含量对5356铝合金组织和性能的影响。结果表明,在真空熔炼条件下,除气、除杂效果显著,氧化夹杂尺寸明显减小且含量大幅降低。Mg元素易于在晶界处形成网状的非平衡相α-Al+Al_3Mg_2。随着5356铝合金中Mg含量提高,合金抗拉强度提高,伸长率下降,最佳的Mg添加量为5.0%。     

微量Sc对6005A合金微观组织与拉伸性能的影响

采用铸锭冶金法制备出不同Sc含量的6005A合金铸锭,合金铸锭经均匀化、热轧、中间退火、冷轧成2.5 mm厚的薄板,研究Sc含量对6005A合金拉伸性能、晶粒大小、金相组织及其相组成的影响。结果表明：微量Sc可提高6005A合金的强度,其中含0.07%Sc的合金具有最佳的拉伸性能,其抗拉强度、屈服强度分别提高19 MPa、47 MPa,伸长率也提高1.2%;添加微量Sc的合金晶粒得到细化,且随着Sc含量的增加,细化效果越明显;添加微量Sc减合金中枝晶的偏析,形成弥散的Al₃Sc相,抑制合金的再结晶;随着Sc含量的增加,晶内弥散的Mg₂Si相得到细化。     

微量元素Sc对ZA27合金组织与性能的影响

试验研究了微量元素Sc对ZA27合金铸态显微组织与力学性能的影响规律。试验结果表明:单独添加合金元素Sc,在Sc的加入量为0.5%时,ZA27合金铸态显微组织细化效果较好,粗大的树枝晶组织转变为均匀、细小的团絮状组织,晶界共晶体组织变得更为细小。合金的铸态抗拉强度和硬度分别达到了495MPa和HB120.2,伸长率达到7.6%。元素Sc在ZA27合金中与Al形成了与基体晶格类型和晶胞尺寸极为相近的Al3Sc粒子,起到了促进异质形核和细晶强化的作用,从而提高了合金的力学性能。     

固溶处理对Al-9.0Zn-2.8Mg-2.5Cu-0.12Zr-0.03Sc铝合金组织性能的影响

采用金相显微镜、差热分析(DSC)和透射电镜(TEM)研究复合添加0.03%Sc 与0.12%Zr 及固溶处理对Al?9.0Zn?2.8Mg?2.5Cu合金组织性能的影响,以及添加少量(小于0.1%)的Sc是否能得到高性能铝合金。结果表明：添加0.03%Sc与0.12%Zr可以使Al?9.0Zn?2.8Mg?2.5Cu合金出现“花瓣状”的Al3(Sc,Zr)析出相;Al3(Sc,Zr)粒子对位错有强烈的钉扎作用,明显抑制 Al?9.0Zn?2.8Mg?2.5Cu 合金在均匀化和挤压过程中的再结晶;多级固溶明显优于单级固溶,可以在添加少量Sc(小于0.1%)时,避免Al?9.0Zn?2.8Mg?2.5Cu发生再结晶：(420°C,3 h)+(465°C,2 h)为最佳固溶条件,此时Al?9.0Zn?2.8Mg?2.5Cu?0.12Zr?0.03Sc合金的抗拉强度为777.29 MPa,伸长率为11.84%。     

通信材料Mg-Zn-Al-Ca合金微观组织及力学性能分析

以通信材料Mg-Zn-Al-Ca合金为研究对象,对不同Al元素的铸态Mg-4Zn-x Al-0.2Ca合金微观组织及力学性能进行试验。结果表明:Mg-4Zn-0.2Ca合金由白色初生-Mg+Mg Zn2共晶组织组成,随Al元素含量不断增加,初生相逐渐变得细小且均匀,合金维氏硬度、弹性模量、和抗拉强度都不断增加,极限抗拉强度呈现先增加后减小的趋势,而断裂伸长率不断减小;当Al元素含量为3%时,该合金极限抗拉强度达到最大值201.8 MPa;当Al元素含量为1%时,合金的断裂伸长率最大值为12.5%。     

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.