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Linking anisotropy with Fe_3C distribution in AISI 1045 steel

International Journal of Minerals,Metallurgy and materials 2015年第12期22卷 1293-1303页

作者： Ke-chang Shen Gui-hua Li Yi-min Sun Yong-gang Wang Ying-jie Li Guang-hui Cao Wei-min Wang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Shandong Institute of Metrology School of Materials Science and Engineering Shanghai University

The anisotropy of the microstructure, thermal expansion behavior, corrosion resistance and magnetic properties of AISI 1045 steel was investigated. The distribution of Fe3C lameUae in the investigation plane parallel to the radial directions of molds was observed to differ from that in the investigation plane perpendicular to the radial directions by transmission electron microscopy. The lattice constants a0 of α-Fe deduced from the XRD patterns of samples prepared using a sand （S）-mold and cut parallel to the radial direction of the mold （S//） and using a metal （M）-mold and cut parallel to the radial direction （M//）, the corrosion resistance measured using an electrochemical work- station, and the magnetic permeability obtained by vibrating sample magnetometry also indicated the existence of anisotropy in the tested samples. The anisotropic change of corrosion potential （Eeorr）, pitting potential （Epit） and magnetic permeability （μ） of the samples was observed to depend on the orientation factorF200 of α-Fe in the measured samples, which is controlled by the distribution of Fe3C lamellae in the eutectoid structure.

关键词： carbon steel microstructure anisotropy lattice constants

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Dielectric properties of porous SiC/Si3N4 ceramics by polysilazane immersion-pyrolysis

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Progress in Natural Science:materials International 2019年第2期29卷 184-189页

作者： Xiao Lin Hongyu Gong Yujun Zhang Jianqiang Bi Yurun Feng Yu Liu Shan Wang Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education Shandong University Key Laboratory of Special Functional Aggregated Materials Ministry of Education Shandong University

The SiC nanotubes were synthesized on porous Si3N4matrix by polysilazane immersion-pyrolysis. The β-SiC and free C contents increased with the increasing dipping times, which cause some clear vibration and loss peaks of the dielectric constant patterns emerged at around 12.9 GHz and 14.7 GHz in the samples of 20 wt% and 30 wt%benzoic acid, respectively. The reflectivity of the obtained ceramics were -7 dB ～-10 dB from the frequency of 8 GHz–18 GHz, which means that the amount of 80%–90% electromagnetic wave could be attenuated. The ceramics containing 40 wt% benzoic acid showed the high loss, low reflectivity and a wide absorbing band,indicating the high absorbing efficiency and good dielectric properties.

关键词： SiC Si3N4 Dipping Dielectric properties

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Correlation between liquid structure and glass forming ability in glassy Ag-based binary alloys

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Science China(Physics,Mechanics & Astronomy) 2010年第3期53卷 399-404页

作者： Lü XiaoQian, BIAN XiuFang, XIANG Nan & JIA Ran key laboratory for liquid-solid Structural evolution and processing of materials (Ministry of Education), Shandong University, Jinan 250061, China 1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Jinan 250061 China

The atomic structures of liquid Ag-based binary alloys have been investigated in the solidification process by means of X-ray diffraction. The results of liquid structure show that there is a break point in the mean nearest neighbor distance r1 and the coordination number Nmin for glass-forming liquid, while the correlation radius rc and the coordination number Nmin display a monotone variational trend above the break point. It means glass-forming liquids have a steady changing in structure above liquidus and more inhomogeneous state at liquidus. We conclude that there is a strong correlation between liquid structure and glass forming ability in Ag-based binary alloys.

关键词： liquid structure glass forming ability Ag-based binary alloys

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Achieving three-layered Al/Mg/Al sheet via combining porthole die co-extrusion and hot forging

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Journal of Magnesium and Alloys 2020年第3期8卷 654-666页

作者： Jianwei Tang Liang Chen Guoqun Zhao Cunsheng Zhang Lu Sun Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinanShandong 250061PR China

Al/Mg/Al sheet with good bonding quality and mechanical properties was fabricated based on the proposed porthole die co-extrusion and forging(PCE-F)*** were no voids,cracks or other defects on the Al/Mg interface.A continuous diffusion zone with two-sub-layer structure was formed across the Al/Mg interface,and its width increased with higher temperature or reduction *** sub-layers formed at low and high temperature were identified to be solid solutions and intermetallic compounds(IMCs)including y-MgpAl^and^-*** Al layer,the welding zone mainly consisted of fine equiaxed grains with several coarse elongated grains,while the majority of matrix zone is coarse elongated *** rolling textures were dominated in both welding and matrix *** Mg layer,the welding zone exhibited complete DRXed grain structure,while several unDRXed coarse grains were observed in the matrix *** the increasing temperature,the grain size of Al and Mg layer firstly decreased and then *** reduction ratio strongly refined the grain structure of Al layer,while slightly affected the Mg *** Al/Mg/AI sheet experienced stress-drops twice during the tensile *** first stress-drop was determined by the IMCs and microstructure of Mg layer,while the second stress-drop was closely related to the microstructure of Al ***/Mg/Al sheet forged at the lowest temperature without the formation IMCs exhibited the highest stress for the first stress-drop,and that forged under the highest reduction ratio with the smallest grain size in Al layer had the highest stress for the second stress-drop.

关键词： Al/Mg/Al Porthole die extrusion Forging Microstructure Mechanical properties.

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Experimental investigation on friction stir welding of 2A12 aluminium alloys

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China Welding 2011年第2期20卷 7-11页

作者：武传松张文斌张志云 Key Lab for Liquid-Solid Structure Evolution and Materials Processing （ Ministry of Education） and Institute of Materials Joining Shandong University Jinan 250061.

Friction stir welding experiments were conducted to study the effects of the process parameters on the weld quality of 2A12 aluminium alloys. Through appropriate selection of the shoulder press amount （axial force）, tool rotation speed and welding speed, good joints were obtained for the test pieces with thickness of 6 ram. The microstructures in weld nugget zone, thermo-mechanical affected zone and heat-affected zone were analyzed. It is found that the ratio of the tool rotation speed to the welding speed should be optimized for a suitable shoulder press amount.

关键词： friction stir welding experimental investigation aluminium alloy

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Effects of controlled pulse current waveform on key-holing condition in plasma arc welding

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China Welding 2010年第2期19卷 12-16页

作者：武传松贾传宝陈茂爱 Key Lab for Liquid-Solid Structure Evolution and Materials Processing （Ministry of Education） and Institute for Materials Joining Shandong University Jinan 250061.

To overcome the shortcomings of conventional plasma arc welding （ PAW）, the ＇ controlled pulse key-holing＇ strategy is proposed and the keyhole PAW experiment system is developed. ＇The efflux plasma voltage signal is detected in realtime to characterize the keyhole size and dimension. The welding current waveform for controlled pulse key-holing strategy is implemented, and two slow-decreasing slopes are added at the dropping point from peak current to base current to further reduce both heat input and arc force so that the controllability of keyhole dynamics is improved. Two kinds of PAW tests are conducted, anti the different parameters of the controlled pulse current and the relevant efflux plasma voltage are measured in real-time to investigate ihe effects of welding current waveform parameters on the key-holing condition.

关键词： plasma arc welding controlled pulse current waveform key-holing condition

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Design and fabrication of NiFe_(2)O_(4)/few-layers WS_(2) composite for supercapacitor electrode material

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Frontiers of materials Science 2023年第3期17卷 83-94页

作者： Xicheng Gao Jianqiang Bi Lulin Xie Chen Liu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China

Few-layers WS_(2) was obtained through unique chemical liquid exfoliation of commercial WS_(2).Results showed that after the exfoliation process,the thickness of WS_(2) reduced ***,the NiFe_(2)O_(4) nanosheets/WS_(2) composite was successfully synthesized through a facile hydrothermal method at 180°C,and then proven by the analyses of field emission scanning electron microscopy,X-ray diffraction,and X-ray photoelectron *** composite showed a high specific surface area of 86.89 m^(2)·g^(−1) with an average pore size of 3.13 ***,in the threeelectrode electrochemical test,this composite exhibited a high specific capacitance of 878.04 F·g^(−1) at a current density of 1 A·g^(−1),while in the two-electrode system,the energy density of the composite could reach 25.47 Wh·kg^(−1) at the power density of 70 W·kg^(−1) and maintained 13.42 Wh·kg^(−1) at the higher power density of 7000 W·kg^(−1).All the excellent electrochemical performances demonstrate that the NiFe_(2)O_(4) nanosheets/WS_(2) composite is an excellent candidate for supercapacitor applications.

关键词： WS_(2) chemical liquid exfoliation NiFe_(2)O_(4) composite supercapacitor

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Analysis of the 3-D fluid velocity and temperature profile in keyhole plasma arc welding

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China Welding 2011年第3期20卷 12-16页

作者：张涛武传松 Key Lab for Liquid-Solid Structure Evolution and Materials Processing （ Ministry of Education） and Institute of Materials Joining Shandong University Jinan 250061.

Modeling and simulation of fluid flow and heat transfer in keyhole plasma arc welding is of great significance for optimizing the process parameters. In this study, a three-dimensional transient model is established to analyze numerically the heat transfer and fluid flow phenomena in keyhole plasma arc welding. VOF （volume of fluid） method is used to track the boundary of the keyhole. The dynamic developments of keyhole geometry, the fluid velocity field and temperature profiles are numerically simulated. And the changing Of the fluid velocity and pressure distribution on the keyhole wall in the forming process of the keyhole are analyzed.

关键词： fluid flow heat transfer numerical analysis keyhole plasma arc welding

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Microstructural evolution in 35CrMnSi steel during multi-cyclic quenching and partitioning heat treatment

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Science China(Technological Sciences) 2013年第10期56卷 2581-2585页

作者： LI Yang XIAO GuiYong CHEN LuBin LU YuPeng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University School of Materials Science and Engineering Shandong University

A novel method,***-cyclic quenching and partitioning(M-Q-P)heat treatment,is used to tailor the content of retained austenite(RA)in commercial *** 35CrMnSi steel,5 times of Q-P heat treatment can increase the content of RA from 8vol.%to 17 vol.%.As a result,the ultimate elongation of the steel is improved from 17.4%after the typical Q-P heat treatment to 27.1%after 5 times of Q-P ***,the improved combination of strength and ductility for steels by typical Q-P heat treatment is retained by the multi-cyclic Q-P heat *** is shown that the content of RA in some specific steels,and furthermore their mechanical properties,can be regulated through the M-Q-P.

关键词： steels martensitic phase transformation quenching and partitioning EMPA

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Thermodynamic determination of fragility in La-based glass-forming liquid

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Chinese Science Bulletin 2011年第36期56卷 3912-3918页

作者： JIA Ran BIAN XiuFang WANG YingYing Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials of Ministry of Education Shandong University Jinan 250061China

Differences in the thermodynamic functions between the liquid and crystalline states of La-based bulk metallic glasses alloys were calculated with the specific heat capacity Cp and the fusion heat ΔHf,which we measured. Fragility indexes having different thermodynamic definitions were calculated from the temperature dependence of excess entropy ΔSliq-cry. It is ambiguous for La-based glass-forming liquid to evaluate fragility from the intercepts of ΔSliq-cry-temperature curves. We found that the thermodynamic fragility MΔS,denoted ΔS,decreases at the onset melting temperatures Tm rather than at glass transition temperatures Tg,and relates linearly with the kinetic fragility m. The correlations between thermodynamic fragility and kinetic fragility are discussed within the frameworks of the Adam-Gibbs relationship and potential energy landscape theory.

关键词：玻璃形成洛杉矶力学测定液体热力学函数玻璃化转变温度 SLIQ 温度曲线

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