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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 Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), Jinan 250061, China (Received 2002-04-11) 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 220 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_2O_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

Effect of mixing temperature on microstructure of an al-si alloy prepared by controlled diffusion solidification

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China Foundry 2023年第3期20卷 241-252页

作者： Han Xue Ti-jun Chen Xue-zheng Zhang Guang-li Bi Ying Ma Ren-guo Guan State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina

The effects of mixing temperature,i.e.,the temperatures of two precursor melts(pure al and al-12si),on the temperature and solute fields of resultant mixture,the nucleation and growth,and the size and morphology of primary grains during controlled diffusion solidification(CDS) of al-8si alloy were investigated by using simulation and *** results indicate that a lower mixing temperature is helpful for achieving more supercooled microscale al-rich pockets in the mixture,and increasing the width and supercooling degree of supercooling zone in the al-rich pockets,and thus,the nucleation *** nuclei grow up in nondendritic mode,resulting in spheroidal,at least,nondendritic *** a successful CDS,the superheat degrees of the two precursor melts should be limited within several degrees,and it is not necessary to extra stipulate the superheat degree of target alloy melt(al-8si) when the requirement about Gibbs energies of the three melts is *** observation on casting microstructures shows that the employed simulation and calculation processes are reasonable and the achieved results are reliable.

关键词： controlled diffusion solidification al-si alloy nucleation and growth supercooling nondendritic grains

Effects of electric pulse on microstructure of al-si alloy in liquid and solid states

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Journal of University of Science and Technology Beijing 2004年第2期11卷 123-126页

作者： JingsongWang QingguoXue GuoweiChang YongTang JianzhongWang DaqiangCang MetallurgicalandEcologicalEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China FacultyofMaterialsandChemicalEngineering LiaoningInstituteofTechnology.Jinzhou121001China DepartmentofMetallurgicalEngineering OuluUniversityOulu94007Finland

In order to investigate the change in liquid microstructure of al-si alloytreated by electric pulse (EP), X-ray diffraction tests with liquid al-si alloy and ZL109 alloytreated or not by EP were carried out. The results show that the number of al-si atomic clustersdecreases and that of al-al and si-si atomic clusters increases for the treated samples. The testswith ZL109 alloy indicate that a large amount of primary crystal si appears in the solidifiedmicrostructure after treated by EP. It is found that EP can change the microstructure of liquidmetal by affecting the probability of electrons appearing in different atoms (al and si) in theliquid metal. The combining force of different atoms decreases relatively, and that of the sameatoms increases, which is the main reason of reducing the atomic cluster with different atoms(al-si) and increasing the atomic cluster with the same atoms (al-al, si-si). The increasing of theatomic cluster with the same atom cluster resulted in the increasing of si activity and the higherpoint of eutectics in the phase diagram. It makes a lot of primary silicon appeared in ZL109 alloy.

关键词： electric pulse treatment al-si alloy ZL109 alloy microstructure X-raydiffraction

Microstructure and performance of al-si alloy with high si content by high temperature diffusion treatment

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Transactions of Nonferrous Metals Society of China 2010年第11期20卷 2134-2138页

作者：修子扬陈国钦王晓峰武高辉刘艳梅杨文澍 School of Material Science and Engineering Harb in Institute of Technology

The al-si alloy with high si content was prepared by pressure infiltration. Microstructure observation shows that three-dimensional structure （3D-structure） is obtained from irregular sharp si particles via high temperature diffusion treatment （HTDT）. Flat si-al interfaces transform to smooth curves, and si phases precipitate in al and si-al interface. The bonding of si-al interface is improved by HTDT, which improves the mechanical performance of al-si alloy. The bending strength of 3D-al-si alloy increases by 6% compared with that of al-si alloy, but the elastic modulus changes a little. The coefficient of thermal expansion （CTE） of the 3D-al-si alloy is 7.7×10^-6/℃ from 20℃ to 100 ℃, which decreases by 7% compared with that of al-si alloy. However, HTDT has little effect on the thermal conductivity of al-si alloy.

关键词： al-si alloy 3D-structure interface diffusion

AN IN siTU SURFACE COMPOsiTE AND GRADIENT MATERIal OF al-si alloy PRODUCED BY ELECTROMAGNETIC FORCE

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Acta Metallurgica sinica(English Letters) 2001年第5期14卷 335-340页

作者： Z.M. Xu, T.X. Li, Z.L. Zhu and Y.H. Zhou School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China School of Materials Science and Engineering Shanghai Jiao Tong University

Because of the different conductivities between the primary phase (low electric conduc tivity) and the metal melt, electromagnetic force scarcely acts on the primary phase. Thus, an electromagnetic repulsive force applied by the metal melt exerts on the pri mary phase when the movement of the melt in the direction of electromagnetic force is limited. As a result, the repulsive force exerts on the primary phase to push them to move in the direction opposite to that of the electromagnetic force when the metal melt with primary phase solidifies under an electromagnetic force field. Based on this, a new method for production of in situ surface composite and gradient material by electromagnetic force is proposed. An in situ primary si reinforced surface composite of al-15wt%si alloy and gradient material of al-l9wt%si alloy were produced by this method. The microhardness of the primary si is HV1320. The reinforced phase size is in the range from 40μm to 100μm. The wear resistance of al-si alloy gradient material can be more greatly increased than that of their matrix material.

关键词： al-si alloy electromagnetic force in situ surface composite gradient material

Microstructure variation and growth mechanism of hypoeutectic al-si alloy solidifi ed under high pressure

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China Foundry 2009年第2期6卷 129-132页

作者： Zhang Guozhi Yu Xifeng Liu Xinggang School of Materials and Metallurgy Northeastern University Shenyang 110004 China

The microstructure of hypoeutectic al-9.21wt.%si alloy solidified under 5.5 GPa was studied. The results show that the solidification microstructure is refined. The primary a phase is the extended solid solution. The solid solubility of si in α phase is up to 8.26wt.%. The growth mode of the α phase is cellular, and this cellular growth mechanism is interpreted in terms of the decrease of the diffusivity and the extended solid solution under high pressure. By calculation, it can be known that the the diffusivity of solute in the liquid under normal pressure is as high as two hundred times that under high pressure. The microhardness of the hypoeutectic al-si alloy solidified under high pressure is higher than that of solidified under normal pressure. After annealing, si precipitates from the solid solution, the microhardness of the alloy decrease, but, still higher than that of solidified under normal pressure.

关键词： al-si alloy high pressure solidification extended solid solution cellular growth

Characterization of the hot deformation behavior of a al-si alloy using processing maps

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Characterization of the hot deformation behavior of a Al-Si ...

Effects of T6 heat treatment on mechanical, abrasive and erosive-corrosive wear properties of eutectic al-si alloy

第八届中国功能材料及其应用学术会议

作者： WANG Ming-liang JIN Pei-peng WANG Jin-hui HAN Li Qinghai Provincial Key Laboratory of New Light alloys Qinghai University

The compression tests of solution treatment ZL109 alloy have been performed in the compression temperature range from 250℃ to 450℃ and the strain rate range from 0.0005s

ISBN: (纸本)9783037859698

The compression tests of solution treatment ZL109 alloy have been performed in the compression temperature range from 250℃ to 450℃ and the strain rate range from 0.0005s

关键词： al-si alloy Hot deformation Processing map Dynamic recrystallization Flow instability

来源： cnki会议评论

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Transactions of Nonferrous Metals Society of China 2012年第5期22卷 1041-1050页

作者： A. K. GUPTA B. K. PRASAD R. K. PAJNOO S. DAS CsiR - Advanced Materials and Processes Research Institute Bhopal-462026 India Central Institute of Agricultural Engineering (ICAR) Bhopal-462028 India

The abrasive and erosive-corrosive properties of eutectic al-si （LM6） alloy were studied. Microstructural features of the alloy were altered by controlling the T6 heat treatment parameter, and their influence on hardness, strength and elongation, and response of the samples in erosion-corrosion and abrasion conditions were studied. Characteristics of the al-si alloy samples were compared with those of al conventionally used in agricultural machineries. Fabrication of a typical component using the al-si alloy was also explored in order to understand the feasibility of using the alloy system for the envisaged applications. The study suggests the response of the samples in different conditions to be greatly influenced by parameters like chemical composition, microstructural features and applied load, traversal distance and test environment. The performance of even the as cast al-si alloy is far superior to that of the conventional al samples, while the T6 heat treated al-si alloy shows improved performance. Accordingly, the as-cast as well as T6 heat treated al-si alloy has potential for applications in agriculture as a replacement for the conventionally used al.

关键词： al-si alloy heat treatment abrasion erosion corrosion

Effect of pre-annealing on microstructure and compactibility of gas-atomized al-si alloy powders

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Transactions of Nonferrous Metals Society of China 2016年第9期26卷 2355-2362页

作者：蔡志勇张纯王日初彭超群邱科王乃光江西理工大学材料科学与工程学院赣州341000 中南大学材料科学与工程学院长沙410083

Effect of pre-annealing treatment temperature on compactibility of gas-atomized al-27%si alloy powders was investigated. Microstructure and hardness of the annealed powders were characterized. Pre-annealing results in decreasing al matrix hardness, dissolving of needle-like eutectic si phase, precipitation and growth of supersaturated si atoms, and spheroidisation of primary si phase. Compactibility of the alloy powders is gradually improved with increasing the annealing temperature to 400 ℃. However, it decreases when the temperature is above 400 ℃ owing to the existence of si-si phase clusters and the densely distributed si particles. A maximum relative density of 96.1% is obtained after annealing at 400 ℃ for 4 h. In addition, the deviation of compactibility among the pre-annealed powders reaches a maximum at a pressure of 175 MPa. Therefore, a proper pre-annealing treatment can significantly enhance the cold compactibility of gas-atomized al-si alloy powders.

关键词： al-si alloy compactibility rapid solidification annealing microstructure