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Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core–shell-structured Ti/Al3Ti

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1431-1437页

作者： Li Zhang Bao-lin Wu Yu-lin Liu School of Materials Science and Engineering Shenyang Aerospace UniversityShenyang 110136China liaoning key laboratory of aviation light alloy and processing technology Shenyang Aerospace UniversityShenyang 110136China

An Al-based composite reinforced with core–shell-structured Ti/Al_3Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620°C for 5 h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core–shell-structured reinforcement, which is mainly composed of Al_3Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al_3Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al–Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.

关键词： microstructure aluminum-based composites Ti/Al3Ti reinforcements mechanical properties

Microstructure and mechanical properties of Al-5.5Fe-1.1V-0.6Si alloy solidified under near-rapid cooling and with Ce addition

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Rare Metals 2018年第12期37卷 1070-1075页

作者： Yu-Lin Liu Lei Luo Ming-Ze Shun Li Zhang Yu-Hua Zhao Bao-Lin Wu liaoning Provincial key laboratory of light alloys and processing technology School of Materials Science and Engineering Shenyang Aerospace University

Al-Fe-V-Si alloys were developed for use at elevated temperature and usually produced through a rapid solidification-powder metallurgy route. In this work, effort was made to produce the material via casting route. The studied alloys were cast under the condition of near-rapid cooling. The influence of Ce addition on microstructure and mechanical properties of near-rapid solidified alloys were investigated. The results indicate that the as-cast microstructure of Al-5.5 Fe-1.1 V-0.6 Si alloy is significantly refined when the alloy was solidified under nearrapid cooling. Adding Ce results in the further refinement of intermetallic compound and the formation of an Al-V-Ce phase which replaces the primary phase Al(Fe,V)Si. The mechanical properties of the alloy are significantly improved by Ce addition: More than 70% increase in tensile strength and elongation is achieved by adding 1.00 wt% Ce to the alloy. It is concluded that near-rapid cooling and Ce addition are effective in improving mechanical properties of cast Al-5.5 Fe-1.1 V-0.6 Si alloy.

关键词： Aluminum alloys Al-Fe-V-Si alloy Rapid solidification Solidification microstructures Mechanical properties

Effect of Fe, Si and Cooling Rate on the Formation of Fe-and Mn-rich Intermetallics in Al–5Mg–0.8Mn alloy

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Journal of Materials Science & technology 2016年第4期32卷 305-312页

作者： Yulin Liu Lei Luo Chaofei Han Liangyun Ou Jijie Wang Chunzhong Liu liaoning Provincial key laboratory of light alloys and processing technology School of Materials Science and Engineering Shenyang Aerospace University

The Fe- and Mn-rich intermetallics are of great effect on the mechanical properties of the AA5083 type alloy （Al-5Mg-0.8Mn）. The effect of Fe, Si and cooling rate on the formation of the intermetallics were investigated by analyzing the microstructures of the alloys with different Fe and Si contents. The results indicated that increasing the Fe content resulted in the increase of the Al6（Fe,Mn） phase in both amount and size. In the alloys with high Fe content, the platelet-like Al6（Fe,Mn） compounds lined up and formed a band. Increasing the content of Si resulted in the increase of the Mg2Si phase which formed a network structure. Increasing the cooling rate significantly refined the intermetallics. However, increasing the cooling rate did not change the characteristic of the intermetallic compounds in the alloys with low or medium Si contents. For the alloys with high contents of Fe and Si under the condition of near-rapid cooling, the Fe- and Mn-rich intermetallic compound changed to the quaternary Al15（Fe,Mn）3Si phase and displayed a fine fish bone or Chinese script structure. The refinement of the intermetallics would allow higher tol- erance of Fe and Si contents in the AA5083 alloy produced, for instance, via the continuous strip casting process.

关键词： Aluminum alloyIntermetallicsPhase transformationCastingRapid solidification

Study on the Deformation Behavior of Mg-3.6%Er Magnesium alloy

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Journal of Rare Earths 2007年第6期25卷 744-748页

作者：王忠军贾维平崔建忠 School of Materials Science and Engineering University of Science and Technology Liaoning The key laboratory of Electromagnetic processing of Materials Ministry of Education Northeastern University

The deformation behaviour of a casting Mg-3.6% Er magnesium alloy after T6 treatment was studied in tensile tests from room temperature to 450 ℃ under different strain rates ranging from 1.0 ×10^-4 to 6.0 × 10^-3 S^-1 Obtained local plateau in the temperature dependence of the ultimate strength （σb） and yield strength （σ0.2） under constant strain rate indicated the presence of dynamic strain ageing （DSA）. Serrated flow was observed at the temperature of 200, 250, and 300 ℃. The observed negative strain rate sensitivity suggested that the serrated flow behavior arose from DSA. The temperature and strain rate dependence of the critical strain for the onset of serrated flow was analyzed using a phenomenological DSA equation, and the apparent activation energy Q for the serrated flow was obtained by calculation.

关键词： Mg-3.6% Er alloy deformation behavior serrated flow dynamic strain aging rare earths

Hot Tearing Susceptibility of AXJ530 alloy Under Low-Frequency Alternating Magnetic Field

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1259-1270页

作者： Xudong Du Feng Wang Zhi Wang Xingxing Li Zheng Liu Pingli Mao College of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China key laboratory of Magnesium alloys and the processing technology of liaoning Province Shenyang 110870China

Herein, a hot tearing measured system with external excitation coil and a differential thermal analysis system with applied magnetic field were used to study the effects of low-frequency alternating magnetic field on the solidification behavior and hot tearing susceptibility(HTS) of the AXJ530 alloy under different magnetic field parameters. The hot tearing volume of the castings was measured via paraffin infiltration method. The microstructure of the hot tearing zone of the casting was observed using optical microscopy and scanning electron microscopy, and the phase composition was analyzed using X-ray diffraction and energy depressive spectroscopy. The experimental results show that the solidification interval of AXJ530 alloy was shortened and the dendrite coherency temperature of the alloy decreased with the increase in frequency of alternating magnetic field. Under appropriate magnetic field parameters, the electromagnetic force could enhance the convection in the melt to promote the flow of the residual liquid phase, refine the microstructure, and optimize the feeding channel in the late solidification stage, which reduced the HTS of the alloy. However, when the magnetic field frequency was increased to 15 Hz, the induced current generated excessive Joule heat to the melt. At this time, the thermal action of the magnetic field coarsened the microstructure of the alloy, resulting in an increase in HTS of the alloy.

关键词： AXJ530 alloy Hot tearing susceptibility Alternating magnetic field Microstructure

Research progress of microstructure control for aluminium solidification process

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Chinese Science Bulletin 2013年第4期58卷 468-473页

作者： WANG XiangJie LUO XiaoXiong CONG FuGuan CUI JianZhong key laboratory of Electromagnetic processing of Materials Ministry of Education Northeastern University Aluminum Corporation of China Ruimin Co. Aluminum Corporation of China Northeast light alloy Co.

Aluminum has been the secondly main metallic material in the world, whose mechanical properties are very important for industrial applications. The sizes and shapes of grains are important in determining the performance in structural applications. How to control the microstructure during solidification process has been a research focus. This paper gives an overview on the recent progress in microstructure control for aluminium alloys solidification process, and introduces the different methods to control the microstructure in detail. The mechanisms of microstructure control for different methods are also discussed. Finally, a brief prospect on future work is presented.

关键词：组织控制凝固过程铝合金微观结构工业应用力学性能 SPECT 金属材料

Effect of addition of minor amounts of Sb and Gd on hot tearing susceptibility of Mg-5Al-3Ca alloy

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Journal of Magnesium and alloys 2023年第2期11卷 694-705页

作者： Xudong Du Feng Wang Zhi Wang Le Zhou Zheng Liu Pingli Mao School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870P R China key laboratory of Magnesium alloys and the processing technology of liaoning Province Shenyang 110870P R China

The effects of addition of minor amount of(0.5 wt.%) antimony(Sb) or gadolinium(Gd) and combined addition of Sb and Gd(0.5 wt.%,respectively) on the hot tearing susceptibility(HTS) of Mg-5Al-3Ca alloy were investigated experimentally using a “T-shaped” hot tearing measuring system. Various solidification parameters of the alloys were measured and calculated through thermal analysis experiments. The microstructure, grain size, and morphology of the crack zone were characterized by scanning electron microscopy and electron backscatter diffraction, and the crystal phases of the alloys were analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy. The results showed that the addition of 0.5 wt.% Gd resulted in the increase in the vulnerable temperature range(Tv) and reduced the eutectic structure content that could participate in feeding, thereby improving the HTS of the alloy. However, addition of 0.5 wt.% Sb or combined addition of Gd and Sb(0.5 wt.%, respectively) to the Mg-5Al-3Ca alloy shortened the Tvand improved the skeleton strength of the alloy, thereby reducing HTS. Moreover, significantly refined structure of Mg-5Al-3Ca-0.5Gd-0.5Sb alloy improved the feeding ability of the eutectic structure, thus the alloy exhibited the lowest HTS.

关键词： Hot tearing susceptibility Mg-5Al-3Ca alloy Thermal analysis Microstructure

Grain refinement and macrosegregation behavior of direct chill cast Al-Zn-Mg-Cu alloy under combined electromagnetic fields

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China Foundry 2015年第5期12卷 333-338页

作者： Yu-bo Zuo Xu-dong Liu Chao Sun Sen-sen Yuan Dan Mou Zhan-zhi Li Jian-zhong Cui key laboratory of Electromagnetic processing of Materials Ministry of Education Northeastern University Giant light Metal technology (Kunshan) Co. Ltd.

The combined electromagnetic fields were achieved by the application of an alternating magnetic field and a stationary magnetic field and were used during direct chill(DC) casting process to control the microstructure and macrosegregation of an Al-Zn-Mg-Cu alloy. Ingot microstructures were analyzed under an optical microscope(Leica DMR). The composition at different locations in the ingots was measured with inductively coupled plasma mass spectrometry(ICP) method. The results showed that the grain structure is transformed from dendrite to equiaxed structure and significantly refined with the application of combined electromagnetic fields. The uniformity of microstructure is also greatly improved. The combined electromagnetic fields show a significant effect on the distribution of elements. The negative macrosegregation in the centre area of the ingot is obviously reduced.

关键词： Al-Zn-Mg-Cu alloy electromagnetic field DC casting microstructure macrosegregation

Research progress on semi-continuous casting of magnesium alloys under external field

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China Foundry 2024年第5期21卷 516-524页

作者： Qi-yu Liao Qi-chi Le Da-zhi Zhao Lei Bao Tong Wang Yong-hui Jia key laboratory of Electromagnetic processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China key laboratory of lightweight Structural Materials Liaoning ProvinceNortheastern UniversityShenyang 110819China key laboratory of light-weight Materials Nanjing Tech UniversityNanjing 210009China

High-performance magnesium alloys are moving towards a trend of being produced on a large scale and in an integrated *** foundational key to their successful production is the high-quality cast *** alloys produced through the conventional semi-continuous casting process inevitably contain casting defects,which makes it challenging to manufacture high-quality *** integration of external field assisted controlled solidification technology,which combines physical fields such as electromagnetic and ultrasonic fields with traditional semi-continuous casting processes,enables the production of high-quality magnesium alloy ingots characterized by a homogeneous microstructure and absence of *** article mainly summarizes the technical principles of those external field assisted casting *** focus is on elaborating the refinement mechanism of different types of electromagnetic fields,ultrasonic fields,and combined physical fields during the solidification of magnesium ***,the development prospects of producing highquality magnesium alloy ingots through semi-continuous casting under the external field were discussed.

关键词： semi-continuous casting electromagnetic field ultrasonic field magnesium alloys refinement mechanism