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Investigation of Thermal-Cycling Transformation Superplasticity of As-Cast zn-5al-RE alloy

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Journal of Rare Earths 2003年第S1期21卷 173-176页

作者：石志强李世春刘宇慧 Key Laboratory of Liquid Structure and Heredity of Materials Shandong University College of Mechanical and Electrical Engineering in the University of Petroleum

Under 20～350 ℃ thermal cycling tensile condition,the as-cast zn-5al-RE alloy can realize transformation superplasticity. Rare-earths added into the alloy can make the strain rate and rupture elongation decrease,while the annealing treatment has an opposite effect. The longer the annealing time,the larger the strain rate and rupture elongation will be. The effect of rare earths on the thermal-cycling transformation superplasticity of zn-5al-RE alloy as-cast is two-faced: on the one side,rare earths can make the eutectic structure of zn-5al-RE alloy fine and thus benefits superplastic deformation. On the other side,rare earths make the diffusion velocity of zn and al decrease and postpone the diffusion coordination process,which will hinder the viscous flow of the interphase boundaries,enhance superplastic deformation stress,and make the strain rate and elongation decrease.

关键词： zn-al alloy superplasticity transformation creep rare-earths

Stored energy analysis of zn-5al eutectic alloy in superplastic deformation

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Rare Metals 2002年第3期21卷 218-223页

作者： SHIZhiqing YEYifu 等 KeyLaboratoryofLiquidstructureandHeredityofMaterials MinistryofEducationShandongUniversityJinan250061China CollegeofResourceandEnvironmentEngineering EastChinaUniversityofScie

The stored energy and the energy release during SPD (superplastic deformation) of a zn-5 al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum elongation and minimum flow stress without hot holding treatment before SPD. Experimental results show that stored energy release process is along with SPD process and is also an impetus to SPD. The as-rolled zn-5al alloy has 48 J/mol stored energy which was measured with DSC (differential scanning calorimeter) and conforms well to the calculated value. The as-rolled zn-5al alloy after SPD with an elongation of 2 500% releases 112 J/mol stored energy. Analysis shows that the strain rate is in direct ratio to the rate of stored energy release.

关键词： zn-al alloy superplasticity stored energy DSC

Extrusion Upsetting Multiple Processing in Sandglass Die

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Rare Metals 2001年第1期20卷 62-65页

作者： Wenlin Lu, Yong Wang, Zezhou Feng, Jintao Hai (Beijing Research Institute of Mechanical & Electrical Technology, Beijing 100083, China Academy of Machinery Science and Technology, Beijing 100044, China) 机械部北京机械所北京 100083 机械部机械科学研究院北京 100044

A new method of getting ultrafine grain size has been investigated, which is called 'Extrusion Upsetting Multiple Processing in Sandglass Die' or 'Sandglass Extrusion' (SE). Since the shape of tested billet can remain unchanged after SE, the billet can be extruded repeatedly in order to get large plastic strain. The ultrafine grain size can be obtained in the billet material due to the large plastic strain and the dynamic recrystallization during SE. The experiments on SE of zn-5% al alloy have been done. The SE technology, microstructures, microhardness and superplasticity of tested material after SE have been studied. The experimental results show that the equal-axial ultrafine microstructures can be introduced to the bulk test material during sandglass extrusion. The high strain rate superplasticity can be realized.

关键词： sandglass extrusion ultrafine grain large plastic strain superplasticity zn-al alloy

Effects　of　Cerium　on　the　Mechanical　Properties　of　the　ZA22／al_2O_3　Composites

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Journal of Rare Earths 1995年第1期13卷 27-31页

作者：于思荣何镇明孟长生陈凯 Jilin Univ of Technology Changchun China

ZA22/al2O3 composites were prepared by means of squeeze casting process. The effects of Ce on the ultimate tensile strength (UTS), impact toughness, and hardness of the composites were studied. The results show that both the UTS and the hardness are improved and the impact toughness is decreased with the increase of the volume fraction of fibers (Vf). After Ce is added ,UTS (Vf>15%) and the hardness are improved at room temperature because of the modification of Ce, but the impact toughness and UTS at elevated temperature are *** filtered action of the fiber preform results in that the influence of the amount of Ce added from 0. 1 wt% to 0. 5 wt% on the mechanical properties of the composites can be ignored.

关键词： Cerium zn-al alloy al2O3 Composite materials Mechanical property

Influence of process parameters on thermal-rate treatment of ZA42 alloy

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Transactions of Nonferrous Metals Society of China 2002年第5期12卷 926-930页

作者：李成栋田学雷赵梅耿浩然 Shandong University Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Ji'nan 250061 College of Mechanical Engineering Shandong University Ji'nan 250061

Sand casting process and directional solidification technique combining thermal-rate treatment(TRT) were used. The influence of process parameters on TRT was investigated according to the values of impact toughness. At the same time, the mechanism of TRT was discussed. The results showed that TRT can improve the impact toughness of this alloy, while the hardness is basically constant. The time of heat preservation should not be more than 5 min. Different forms of cooling intensification additive have different effects among which the zinc ingot solidified in graphite mold is the best one that can improve impact toughness of samples by more than 80%. With increasing the cooling temperature, the value of α(al) crystal lattice constant increases. The element Sb has negative effect on TRT.

关键词： zn-al alloy thermal-rate treatment(TRT) parameters

Microstructure and Properties of ZA-27TiRE alloy

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Rare Metals 1993年第1期12卷 16-20页

作者：赵显欧胡汉起王佩君杨国均韩青有 Beijing Research Institute of Prosthetics and Orthotics Ministry of Civil Affairs of China. Beijing China 100020 University of Science and Technology Beijing. Beijing China 100083

The influence of RE and Tion ZA-27 casting alloy was studied. The results show that RE and Ti refine microstructure of the alloy and improve its mechanical properties and wear-resistance, which make it possible to use... 详细信息

关键词： zn-al alloy Mechanical properties Wear-resistance Ti RE