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Role of C and Fe in Grain Refinement of an AZ63B Magnesium Alloy by Al-C Master Alloy

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Journal of materials Science & Technology 2005年第6期21卷 822-826页

作者： Yichuan PAN+, Xiangfa LIU and Hua YANG key laboratory of {2. structure and heredity of materials, ministry of education, Shandong university,jinan 2.0061. china key laboratory of {2. structure and heredity of materials Shandong University Jinan 250061 China

In this study, grain refining effect of Al-1.5℃ master alloy was examined on an AZ63B magnesium alloy, and the refining mechanism was studied through investigating the role of C and Fe in this process. The results show that addition of Al-1.5℃ master alloy leads to significant decrease of the mean grain size from about 2.0μm to 50μm at the center of the AZ63 alloy ingot. Grain refinement by carbon addition is mainly due to the heterogeneity nucleation on the Al-, C-, O-, Fe- and Mn-rich particles, but not constitutional undercooling caused by the carbon solute element. Fe plays an important role in the formation of the nucleating particles, but not acts as an inhibiting element.

关键词： Grain refinement AZ63B Magnesium Al-C master alloy Nucleating particle

Study on the cluster of floating dross before nucleating during hot-dipping process

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Science china Chemistry 2005年第1期48卷 83-88页

作者： WEI Yunhe1, ZHANG Changqiao1, QIN Jingyu2.& LIU Chengbu1 1. School of Chemistry and Chemical Engineering, Shandong university, jinan 2.0100, {2. 2. the key laboratory of liquid structure and heredity of materials of ministry of education, Shandong university, jinan 2.0061. china 1. School of Chemistry and Chemical Engineering Shandong University 250100 Jinan China 2. the key laboratory of liquid structure and heredity of materials of ministry of education Shandong University 250061 Jinan China

During hot-dipping in molten Zn-55Al, the forming of “floating” dross is closely re- lated with the interaction between the Al and the Fe atoms. Utilizing the thita-thita X-ray diffraction and the Percus-Yevick hard sphere model, this paper investigates the structure of molten Al3Fe that is an approximant of partial melt in practical Zn-55Al alloy melt. It is found that in the melt there exist clusters that resemble the structure of intermetallic compound Al3Fe. The strong in- teraction between Al and Fe atoms is also indicated by the deficiency of the coordination number from 12.and the shrinkage of averaged atomic diameter. Based on such information, it is specu- lated that in the molten Zn-55Al, with the accumulation of Fe, Al3Fe-like clusters form with priority, then grow into dross. On the other hand, after deflating of the effective hard sphere diameter of pure Al atom and enlarging that of the pure Fe atom, the modified model can achieve reasonable fit to the experimental structure factor. Hard sphere modeling also gave a good estimation of the mass density 3.65 g/cm3 of liquid Al3Fe alloy at 1550℃. Compared with the density of 3.7 g/cm3 of Zn-55Al, the reason for dross floating is satisfactorily understood.

关键词： hot-dipping, dross, Al3Fe alloy, molten structure, P-Y model.

Microstructure and Tensile Properties of ZK60 Alloy Fabricated by Simplified Rapid Solidification Powder Metallurgy (S-RS P/M) Process

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Journal of materials Science & Technology 2010年第2期26卷 151-155页

作者： Zhenya Zhang, Huashun Yu , Shaoqing Wang, Haitao Wang and Guanghui Min key laboratory of {2. structure and heredity of materials, ministry of education, Shandong university, jinan 2.0061. china [a] key laboratory of {2. structure and heredity of materials ministry of education Shandong university jinan 2.0061 china

This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy （RS P/M） processing system （S-RS P/M）, which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 #m in width. TEM （transmission electron microscopy） observations illustrated nano-size magnesia particles （10-30 nm） constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2. yield strength of S-RS P/M ZKO0 alloy was found to be as high as 382.MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coefficient of thermal expansion （CTE） mismatch because of the approximately same average grain size.

关键词： Microstructure Mechanical properties Rapid solidification powder metallurgy Nano-size magnesia

Fabrication of ceramic layer on an Al-Si alloy by MAO process

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Rare Metals 2003年第2期22卷 103-106页

作者： SONG Xigui, BIAN Xiufang, QI Xiaogang, and ZHANG Junyankey laboratory of {2. structure and heredity of materials, ministry of education, Shandong university (Southern Campus), jinan 2.0061. china (Received 2.02.04-11) Shandong university (Southern Campus) Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Jinan 250061 Shandong university (Southern Campus) Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Jinan 250061

The MAO (Micro-Arc Oxidation) process is applied to a eutectic Al-Si alloy(Al-12.0 percent Si-l.0 percent Cu-0.9 percent Mg (mass fraction)). The oxide ceramic layer wasfabricated with about 2.0 mum thickness and 3000 Hv micro-hardness. By XRD (X-ray diffractometry)and DSC (differential scanning calorimetry) analyses, the oxide layer consists of amorphous Al_2._3,which is distinct from the results reported by the other researchers. The SEM photographs of suchlayer show that the layer is fixed tightly on the substrate alloy. So this alloy can he used in thehigh temperature and friction environment alter it is treated with such process.

关键词： metal material ceramic layer MAO process Al-Si alloy

Nanocrystal Model for liquid Metals and Amorphous Metals

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Journal of materials Science & Technology 2010年第1期26卷 69-74页

作者： X.L. Tian, C.W. Zhan, J.X. Hou, X.C. Chen and J.J. Sun key laboratory of {2. structure and heredity of materials, ministry of education, Shandong university, jinan 2.0061. china [a] key laboratory of {2. structure and heredity of materials ministry of education Shandong university jinan 2.0061 china

A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles （BPPs） of Cu, Al, Al65Cu2.Fe15 alloy, Cu7oNi30 alloy and Fe50Si50 alloy were gained by broadening the X-ray diffraction （XRD） peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the FesoSiso alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster {2. of the liquid metal is similar to the {2. of its crystal lattice.

关键词： liquid metal Atomic cluster structure Crystal lattice

Formation of superthick Al-based amorphous ribbon

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Chinese Science Bulletin 2003年第19期48卷 2145-2147页

作者： WANG Shenghai, BIAN Xiufang & JIA Yubo key Lab of liquid {2. and heredity of materials, ministry of education of china, South Campus of Shandong university, jinan 2.0061. china key Lab of liquid {2. and heredity of materials Ministry of Education of China South Campus of Shandong University China

The Al-Ni-La-Ce-Pr-Nd amorphous ribbon with a super-thickness of 140 mm has been produced by the melt spinning technique. The thickness is as twice as that achieved by the melt spinning technique in the corresponding period (the largest thickness of 65 mm). The crystallization was characterized by using a differential scanning calorimetry. The activation energies are calculated based on the Kissinger equation and the effects of the La, Ce, Pr and Nd on the glass forming ability of Al-based alloy are discussed in the paper.

关键词：铝基非晶形合金熔体纺丝玻璃成型性能固相反应

Influence of nickel and copper on liquid structure of CuAlNi shape memory alloys

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Chinese Science Bulletin 2002年第1期47卷 85-88页

作者： PAN Xuemin & BIAN Xiufangkey laboratory of {2. structure and heredity of materials, education ministry, Shandong university, Ji’nan 2.0061. china key laboratory of {2. structure Education Ministry Shandong University Ji'nan 250061 China

liquid structure of molten pure Cu, Cu-12.l, Cu-12.l-4Ni (mass fraction, %) alloys has been investigated using the X-ray diffraction method. It is found that the main peak of the structure factor of pure Cu is symmetrical. In the front of main peak, the curve takes on a shape of parabola, whereas a distinct pre-peak has been found around a scattering vector magnitude of 18.5 nm-1 in the structure factor of the liquid Cu-12.l alloy. This pre-peak increases its inten-sity with the addition of Ni in the liquid Cu-12.l-4Ni alloy. The appearance of a pre-peak is a mark of the mediate-range order. Based on Daken-Gurry theory and according to mu-tual interaction between unlike atoms, the analysis of corre-lation between different composition and liquid structure was done: the strong interaction exists between Cu and Ni, so Cu-Al can form strong chemical bond which causes compound-forming behavior. Therefore, the medium-range size clusters can form in melt. The presence of the pre-peak corresponds to these

关键词： Cu-12.l-4Ni alloy liquid structure shape memory alloy X-ray diffraction.

Gradual solution heat treatment of AlSiCuMg cast alloys

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Rare Metals 2003年第4期22卷 304-308页

作者： WANG Guiqing , BIAN Xiufang ,and ZHANG Junyan1) The key laboratory of {2. structure and heredity of materials, ministry of education, Shandong university, jinan 2.0061. china2. Department of Material Science and Technology, Shandong Architectural Engineering Institute, jinan 2.0014, china Shandong university The Key Laboratory of Liquid Structure and Heredity of MaterialsMinistry of Education Jinan 250061

The microstructure characteristics of AlSiCuMg cast alloys were studied withdifferent Cu content and the gradual solution treatment by DSC, SEM, TEM and mechanical method. Themelting point of alpha (Al) + Si decreases and polynary eutectic phases with low melting point formwith increase of Cu content. Gradual solution treatment includes two steps: solution treating nearthe melting point of polynary eutectic phase to take it dissolve first, and then increasing solutiontemperature to take the remainder copper intermetallics dissolved into alpha (Al). Grain boundariesmelting can be avoided by gradual solution treatment, even the maximum solution temperature isabove final solidification point, and the age hardening response increases correspondingly

关键词： aluminum alloy gradual solution heat treatment differential scanningcalorimetry (DSC) polynary eutectic phase

Effect of Cerium on the Viscosity of liquid Fe-C Alloy of Eutectic Content

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Journal of Rare Earths 2002年第6期20卷 630-634页

作者：滕新营叶以富key laboratory of {2. structure and heredity of materials ministry of education South Campus of Shandong university 刘含莲王焕荣石志强耿浩然 key laboratory of {2. structure and heredity of materials Ministry of Education South Campus of Shandong University College of Mechanical Engineering Shandong University

The viscosities of liquid Fe-4.30C and Fe-4.30C-Ce alloys were measured by oscillating crucible viscometer. The results show that viscosity of Fe-4.30C alloy changes from 5.50 to 8.30 MPa·s when the liquid is cooled from 142. ℃ to the melting point. The abnormity of viscosity of Fe-4.30C alloy near the melting point is reasonable due to the formation of graphite. The addition of cerium especially with content higher than 0.2.% causes an evidently decrease in viscosity for eutectic alloy resulting from increase of free volume and size decrease of atom cluster in the liquids. It can be concended that the existence of C-Ce compound contributes to the discontinuous of viscosity at 1340～1370 ℃ for the Fe-4.30C-Ce alloy by experinments with differential scanning calorimeter.

关键词： rare earths cerium viscosity liquid eutectic Fe-C alloy