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| 1 | Effects of Cd and Sn on double-peak age-hardening behaviors of Al-Si-Cu-Mg cast alloys显示文摘The effects of trace elements Cd and Sn on precipitation process of Al-Si-Cu-Mg cast alloys were investigated in the present research.It is shown that the addition of Cd and Sn not only increases remarkably the aging peak hardness and reduces the time to reach aging peak,but also eliminates the double-aging-peak phenomenon which appears in Al-Si-Cu-Mg alloys.In Al-Si-Cu-Mg alloys the first aging peak corresponds to GP zones(especially GPⅡ) ,and the second one is caused by metastable phases.The obvious time interval of transition from GPⅡ to metastable phases associates with the double-aging-peak phenomenon.The results of DSC and TEM show that Cd/Sn elements suppress the formation of GPⅠzone,stimulate the formation of θ',θ' and θ phases,and then shorten remarkably the temperature intervals of each exothermic peak.Because the transition interval between GPⅡzone and metastable phases is shortened by Cd/Sn in Al-Si-Cu-Mg cast alloys,θ' phase coexists with θ' phase in matrix of ageing peak condition,which causes effective hardening on the alloys,and at the same time,eliminates the double-aging-peak phenomenon. | Li Runxia Chen Yujin Yuan Xiaoguang Qu Yingdong Li Rongde | 2010 | China Foundry2010，7，1： | 7 |
| 2 | Study on Modification Mechanism of Rare Earth in ZA27 Cast Alloy with Electronic Theory and Molecular Dynamics Method显示文摘A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent α phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE in α phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure. | Guili LIU, Rongde LI and Zhenping ZHOUSchool of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023, China | 2004 | Journal of Materials Science & Technology2004，20，5： | 6 |
| 3 | Application of digital pattern-less molding technology to produce art casting显示文摘Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufacturing technology for castings, integrated with CAD/CAM, casting, CNC machining and many other advanced technologies. With this digital casting technology, no pattern is needed for making molds; it is precise, f lexible, and green. Usually, art castings have complex structures and are made in small batches or even made in a single-piece, especially for large-sized art castings. So it has the shortcomings of high cost, low eff iciency and long time for making a pattern to produce art castings with the conventional casting processes. However, the digital pattern-less casting technology can be applied to fabricate art castings, since it can greatly shorten the manufacturing cycle and lower the production cost, thus having a very good prospect. In this study, based on the digital pattern-less casting technology, a plaque casting with artistic Chinese characters(a Chinese poem) was designed and manufactured, and the production process was demonstrated in detail. | Chen Li Zhang Wei Wu Chenhong Jia Baochang Xiang Qingchun Qiu Keqiang Li Rongde | 2014 | China Foundry2014，11，6： | 5 |
| 4 | Low temperature impact toughness and fracture mechanism of cast QT400-18L ductile iron with diferent Ni additions显示文摘Different contents of Ni(0.3wt.%to 1.2wt.%)were added to the QT400-18L ductile iron to investigate the effect of Ni addition on the impact toughness of cast ductile irons at low temperatures.The impact toughnesses of the samples at room and low temperatures were tested.The microstructures and fractographs were observed.Results show that with the increase of Ni addition there is a general trend of refinement of the ferrite matrix while the nodule density shows no obvious change.When the Ni content is 0.7wt.%,the matrix structure is the refined ferrite with a very small fraction(about 2%)of pearlite near the eutectic cell boundaries.When the Ni content is further increased,the fraction of pearlite increases significantly and reaches more than 5%when 1.2wt.%Ni is added.The impact toughness at room temperature increases as the content of Ni increases from 0.3 wt.%to 0.7 wt.%,but decreases as the Ni content further increases to 1.2wt.%due to the increase of pearlite fraction.The maximum value of the impact work is 18.5 J at room temperature with 0.7wt.%Ni addition.The average value of the impact work is still more than 13 J even at-30℃.In addition,the fracture mechanism changes from ductile manner to brittleness as the testing temperature decreases from 20℃to-60℃. | Zhang Xinning Qu Yingdong Yang Hongwang Li Rongde | 2013 | China Foundry2013，10，5： | 2 |
| 5 | Methods of Measuring and Decomposing the Income Gap: A Survey显示文摘本文按研究对象将收入差距划分为总体收入差距和组群收入差距两大类,从收入不平等、极化和组群收入差距三个层面梳理了收入差距的测度及其分解方法。其中,收入不平等侧重于对总体收入差距的刻画;极化着眼于收入分布中的“聚集”或“扎堆”现象,其衡量指标大体上可分为两极分化测度指标和多极分化测度指标。在收入差距的分解上,Shapley分解和组群收入差距的分布分解方法都是较为前沿的研究领域。文章还强调了各种收入差距衡量指标或分解方法的适用性和针对性,以便有的放矢地选用合适的相关指标和方法,更精准地探寻收入差距的成因。 | Guo Jiqiang Jiang Li Lu Lili Ye Rongde Fei Shulan | 2011 | Social Sciences in China2011，32，3： | 2 |
| 6 | Efects of minor amounts of scandium on microstructure and mechanical properties of ZA27 alloy显示文摘The influences of minor amounts of scandium on the microstructure and mechanical properties of as-cast ZA27 alloy have been experimentally investigated.The experimental results show that as far as the Sc addition is individually concerned,the refinement result of the as-cast ZA27 alloy with 0.5wt.%Sc addition is comparatively better.After alloying with minor amounts of Sc,the coarse dendrites of the ZA27 alloy are refined and transformed into the uniform and small equiaxed grain microstructure;also the eutectics among the grain boundaries become finer.The test results of mechanical properties show that the tensile strength and hardness of the as-cast ZA27 alloy containing 0.5wt.%Sc approach 495 MPa and 120.2 HB,increase by28.5%and 33.1%,respectively,compared with those of the ZA27 alloy with no addition of Sc element,while the elongation of the alloy is improved to 7.6%from 2.7%.The SEM,EDAX and XRD analyses show that in the ZA27 alloy,the trace element Sc combines with Al to form the square Al3Sc phase particles,which serve as heterogeneous nuclei,facilitating the refinement of the microstructure and the improvement of the mechanical properties of the alloy. | Xiang Qingchun Zhang Wei Wang Ruichun Qiu Keqiang Li Rongde | 2013 | China Foundry2013，10，5： | 1 |
| 7 | Modeling solidification structure evolution and microsegregation under pressure condition显示文摘Solidification microstructure and microsegregation were simulated under a constant pressure condition using the cellular automaton method. First, a single dendrite evolution was simulated and compared under pressure condition and under normal condition,respectively. The solidification microstructure and microsegregation were then simulated. Through simulation, it may be concluded that if the growth direction of the dendrite is parallel to the pressure direction, dendrite growth will be hindered. On the other hand,pressure has no influence on the dendrite evolution. However, when two dendrites grow in close contact, solute enrichment occurs in the dendrites, which hinders the growth of the dendrites. In addition, the solute is preferentially enriched along the pressure direction. | Qiang Li Qiaoyi Guo Rongde Li | 2006 | Journal of University of Science and Technology Beijing2006，13，6： | 0 |
| 8 | Effects of scandium and zirconium combination alloying on as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy显示文摘The influences of minor scandium and zirconium combination alloying on the as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy have been experimentally investigated.The experimental results show that when the minor elements of scandium and zirconium are simultaneously added into the Al-4Cu-1.5Mg alloy,the as-cast microstructure of the alloy is effectively modified and the grains of the alloy are greatly refined.The coarse dendrites in the microstructure of the alloy without Sc and Zr additions are refined to the uniform and fine equiaxed grains.As the additions of Sc and Zr are 0.4% and 0.2%,respectively,the tensile strength,yield strength and elongation of the alloy are relatively better,which are 275.0 MPa,176.0 MPa and 8.0% respectively.The tensile strength is increased by 55.3%,and the elongation is nearly raised three times,compared with those of the alloy without Sc and Zr additions. | Xiang Qingchun Zhao Jing Pan Haicheng Hou Lina Li Rongde | 2011 | China Foundry2011，8，1： | 0 |
| 9 | Sn60Pb40 solder powders produced by the planar flow casting atomization process显示文摘Conventional planar flow casting(PFC) is one of rapid solidification processes for the fabrication of microcrystalline or amorphous ribbons.Based on the conventional PFC process,the planar flow casting atomization(PFCA) process has been developed,which is a new rapid solidification process for the production of metal powder directly from alloy melts.A prototype experimental apparatus was designed and manufactured.With the apparatus,Sn60Pb40 alloy solder powders were prepared,and the effects of the main technological parameters on the powder size distribution and morphology were experimentally studied.The experimental investigations indicate that the metal powders produced by the PFCA process can be classified by velocity;and fine spherical tin-lead alloy solder powders can be fabricated by adjusting the technical parameters.The new PFCA process has such features as high productivity and efficiency,low energy consumption,simple operation,short technological process,and large gross yield. | Xiang Qingchun Zhao Jing Pan Haicheng Li Rongde | 2011 | China Foundry2011，8，2： | 0 |
| 10 | Letter of Invitation显示文摘 | Li Rongde | 2008 | China Foundry2008，5，1： | 0 |
| 11 | Morphology and microstructure of rapidly solidified tin-lead alloy powders显示文摘Sn60Pb40 alloy powders were fabricated using the planar flow casting(PFC) atomization process. By using OM, SEM and EPMA, the characteristics of the morphologies and microstructures of the powders have been investigated. It is observed that the environment of ambient gas in the atomization box has great effects on the morphology of the alloy powders. The microstructures of Sn60Pb40 alloy powders produced by the PFC atomization process are completely composed of eutectic, which is made up of both oversaturated α solid solution and β solid solution. The microstructures of small size powders are extraordinarily undeveloped dendritic eutectic, in which the large majority of the α phase appears nearly spherical, evidently since the cooling rate is higher and the under-cooling is larger. As for the large size powders, since the cooling rate and undercooling are relatively low, lamellar α phase apparently increases in the eutectic microstructures of these powders, and there is even typical lamellar eutectic structure clearly observed in some micro-areas. After remelting tests by DTA, the microstructures of small size powders are transformed, which become composed of large crumby α phase and eutectic(α+β), while those of large size powders change into classical tin-lead structures of primary α phase plus lamellar eutectic(α+β). By studying the microstructures of tin-lead alloy powders, a model has been proposed to predict the microstructure formation of Sn60Pb40 alloy powders. | Xiang Qingchun Zhang Wei Qiu Keqiang Qu Yingdong Li Rongde | 2014 | China Foundry2014，11，5： | 0 |
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