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Nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy 被引量:5
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作者 孙瑜 庞绍平 +2 位作者 刘学然 杨子润 孙国雄 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2186-2191,共6页
The nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy was investigated using optical microscopy and scanning electron microscopy equipped with electron backscattering diffraction(EBSD).By revealing ... The nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy was investigated using optical microscopy and scanning electron microscopy equipped with electron backscattering diffraction(EBSD).By revealing the eutectic cells and analyzing the crystallographic orientation,it was found that both the eutectic Si and Al phases in an eutectic cell were not single crystal,representing an eutectic cell consisting of small 'grains'.It is also suggested that the eutectic nucleation mode can not be determined based on the crystallographic orientation between eutectic Al phases and the neighboring primary dendrite Al phases.However,the evolution of primary dendrite Al phases affects remarkably the following nucleation and growth of eutectic cell.The coarse flake-fine fibrous transition of eutectic Si morphology involved in impurity elements modification may be independent of eutectic nucleation. 展开更多
关键词 hypoeutectic al-si alloy eutectic cell NUCLEATION GROWTH
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Grain refining mechanism of Al-3B master alloy on hypoeutectic Al-Si alloys 被引量:11
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作者 刘源 丁超 李言祥 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1435-1440,共6页
Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of... Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of Al-7Si. It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency. On the basis of experiments and theoretical analysis, a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys. The formation of 'Al-AlB2' shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α(Al) phase. 展开更多
关键词 Al-3B master alloy hypoeutectic al-si alloys nucleation mechanism grain refinement
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Research on semi-solid slurry of a hypoeutectic Al-Si alloy prepared by low superheat pouring and weak electromagnetic stirring 被引量:21
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作者 LIU Zheng MAO Weiming ZHAO Zhengduo 《Rare Metals》 SCIE EI CAS CSCD 2006年第2期177-183,共7页
The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were inve... The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were investigated. The results indicated that the semi-solid slurry to satisfy rheocasting can be manufactured by low superheat pouring and weak electromagnetic stirring. The pouring temperature (or superheat) and the stirring power remarkably affected the morphology of primary α-Al and the size of primary α-Al, and there is no obvious effect of stirring time on primary α-Al. Compared with the samples made by low superheat pouring with no stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 were markedly improved by low superheat pouring and weak electromagnetic stirring. On the condition of weak electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effectiveness obtained from the lower pouring temperature without stirring. 展开更多
关键词 SEMI-SOLID low superheat pouring weak electromagnetic stirring hypoeutectic al-si alloy A356 Al alloy
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Growth mechanism of primary silicon in cast hypoeutectic Al-Si alloys 被引量:10
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作者 王守仁 马茹 +2 位作者 王英姿 王勇 杨丽颖 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第6期1264-1269,共6页
The microstructural features of hypoeutectic AI-10%Si alloy were observed using optical microscopy and electron backscatter diffraction. The results show that primary silicon particles are frequently found in hypoeute... The microstructural features of hypoeutectic AI-10%Si alloy were observed using optical microscopy and electron backscatter diffraction. The results show that primary silicon particles are frequently found in hypoeutectic alloys. Hence, the nucleation and growth mechanisms of the precipitation of primary silicon of hypoeutectic Al-10%Si alloy melts were investigated. It was discovered that Si atoms are easy to segregate and form Si-Si clusters, which results in the formation of primary silicon even in eutectic or hypoeutectic Al-Si alloys. In addition, solute redistribution caused by chemical driving force and large pile-ups or micro-segregation of the solute play an important role in the formation of the primary silicon, and the solute redistribution equations were derived from Jackson-Chalmers equations. Once Si solute concentration exceeds eutectic composition, primary silicon precipitates are formed at the front of solid/liquid interface. 展开更多
关键词 al-si alloys SOLIDIFICATION crystal growth primary silicon solute redistribution
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Refining Effect of Boron on Hypoeutectic Al-Si Alloys 被引量:1
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作者 Li WANC+ and xiufang BIAN (Shandong University of Technology, Jinan 250061, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第5期517-520,共4页
Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the a-AI and eutectic Si with the different additions of Al-B master alloys made at ... Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the a-AI and eutectic Si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AIB2 particles; slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AI-B master alloy can refine not only a-AI, but eutectic Si. Theoretical analysis indicates that, although AIB2 does not take part directly in the nucleation process in pure Al in the presence of Si, it provides a substrate for precipitation of a small content of Si from which a-At will grow without any undercooling. When the temperature decreases to eutectic line, AIB2 subsequently nucleates eutectic Si; AIB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions. 展开更多
关键词 AL Refining Effect of Boron on hypoeutectic al-si alloys SI
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Effects of Si Content and the Addition Amount of Al-3B Master Alloy on the Solidification Structures of Hypoeutectic Al-Si Alloys
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作者 Donghui Wang,Jianguo Li, Yankang Zheng, Bingzhe Bai Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China 《Rare Metals》 SCIE EI CAS CSCD 2001年第3期168-173,共6页
Effects of Si content and the addition amount of Al-3B master alloy on the solidification structures of hypoeutectic Al-Si alloys were studied. The addition amounts of the master alloy were 0.2%, 0.4%, 0.7% and 1% (ma... Effects of Si content and the addition amount of Al-3B master alloy on the solidification structures of hypoeutectic Al-Si alloys were studied. The addition amounts of the master alloy were 0.2%, 0.4%, 0.7% and 1% (mass fraction, so as the follows), respectively. The Si content of Al-Si binary alloys investigated varied from 1% to 11%. The observation of macrostructures of non-refined samples showed that 3% Si constitutes a transition point at which the minimum grain size can be obtained. It was also found that Al-3B master alloy can shift the transition point towards a higher Si value when its addition amount increases, making this point appear at 4%, 5% and 6% Si as its addition amount increases up to 0.4%, 0.7% and 1%, respectively. 展开更多
关键词 Al-3B master alloy hypoeutectic al-si alloy grain refinement
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Manufacture technique of semi-solid slurry of hypoeutectic Al-Si alloy by low superheat pouring and weak electromagnetic stirring 被引量:11
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作者 LIU Zheng MAO Wei-ming ZHAO Zheng-duo 《China Foundry》 SCIE CAS 2006年第2期102-107,共6页
The semi-solid slurry of hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouring temperature and stirring power on the semi-solid slurry making proc... The semi-solid slurry of hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouring temperature and stirring power on the semi-solid slurry making process were investigated. The results indicate that the semi-solid slurry to satisfy rheocasting requirement can be made by a combination of low superheat pouring and weak electromagnetic stirring. The pouring temperature (or superheat) and the stirring power significantly affect the morphology and the size of primary α-Al, while there is no obvious effect of the stirring time on primary α-Al. Compared with the samples made by low superheat pouring without stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 Al alloy are markedly improved by a process of applying both low superheat pouring and weak electromagnetic stirring. Under the condition of weak electromagnetic stirring applied, the pouring temperature with low superheat can be equivalently to reach the effectiveness obtained from the even lower pouring temperature without stirring. 展开更多
关键词 SEMI-SOLID low SUPERHEAT POURING weak electromagnetic STIRRING hypoeutectic al-si alloy A356 Al alloy
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Distributions of Sr and Fe and their influence on modification of hypoeutectic Al-Si alloy 被引量:3
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作者 Tu Lan Jian-guo Li 《China Foundry》 SCIE 2016年第2期85-92,共8页
The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were ex... The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were examined using scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDX). A new method of electron probe microanalysis(EPMA) map scanning was used to analyze the Sr distribution, which gave quantitative results covering more Si particles. EPMA map scanning, together with SEM with EDX, was also used in analyzing the distribution of Fe phases. Results show that Fe-containing phase was related to the unmodified Si particles in samples with partial modification failure and the plate-like Si phases in samples without modification failure. Such a relationship was further confirmed by the microstructure observation.In conclusion, a partial failure of Sr-modification can be caused by both slow cooling rate and Fe-containing phases. 展开更多
关键词 al-si alloys cooling rate modification theory Sr segregation Fe-contained phases
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Effects of vibration and grain refiner on microstructure of semisolid slurry of hypoeutectic Al-Si alloy 被引量:8
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作者 赵君文 吴树森 +2 位作者 谢礼志 安萍 毛有武 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第4期842-846,共5页
The effects of vibration and grain refiner on the microstructure of semisolid slurry of hypoeutectic Al-Si alloy were studied. The impact of vibration on the convection of liquid was conducted by using a system of wat... The effects of vibration and grain refiner on the microstructure of semisolid slurry of hypoeutectic Al-Si alloy were studied. The impact of vibration on the convection of liquid was conducted by using a system of water-particle tracer. The 356 melt at temperature of 630-660 ℃ with or without grain refiner Al-5%Ti-1%B was poured into a metal cup as the vibrating vessel, then it was cooled to 590-610 ℃ in the semisolid zone and kept for some time, subsequently vibration with different frequencies was applied. The results show that the primary α(Al) particles become finer and rounder with the increase of vibration frequency. The slurry with primary α(Al) equivalent particle diameter(EPD) of about 90 μm and average shape coefficient(ASC) of about 0.5 can be prepared under vibration of 20 Hz. With the combined action of vibration and grain refiner Al-5Ti-B, even smaller and rounder spheroids with EPD of about 85 μm and ASC of about 0.6 are obtained. 展开更多
关键词 亚共晶铝硅合金 机械振动 半固态金属 晶粒细化剂 微观结构
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Microstructure variation and growth mechanism of hypoeutectic Al-Si alloy solidifi ed under high pressure
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作者 Zhang Guozhi Yu Xifeng Liu Xinggang 《China Foundry》 SCIE CAS 2009年第2期129-132,共4页
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 ... 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. 展开更多
关键词 al-si alloy high pressure solidification extended solid solution cellular growth
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Grain refinement of hypoeutectic Al-Si alloy prepared with ELTA by A1-4B master alloy
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作者 王明星 孟祥永 +4 位作者 刘志勇 刘忠侠 翁永刚 宋天福 杨升 《中国有色金属学会会刊:英文版》 CSCD 2006年第A03期1342-1345,共4页
Electrolytic low-titanium aluminum (ELTA) was produced by adding TiO2 powder to an industrial aluminum electrolyzer. The grain refining effect of A1-4B master alloy in the hypoeutectic Al-Si alloy prepared by using EL... Electrolytic low-titanium aluminum (ELTA) was produced by adding TiO2 powder to an industrial aluminum electrolyzer. The grain refining effect of A1-4B master alloy in the hypoeutectic Al-Si alloy prepared by using ELTA was investigated, and compared with those of Al-5Ti, A1-5Ti-1B and Al-4B master alloys in the similar alloy prepared by using pure Al. The results indicate that when Al-4B is added to the melt of the alloy prepared by using ELTA in terms of the Ti/B mass ratio of 5:1, the grain refining effect is better than those of Al-5Ti, Al-5Ti-1B and Al-4B master alloys. Thus, using Al-4B to refine the grain of Al-Si alloys prepared by using ELTA will possibly become a feasible way of obtaining Al-Si alloy with homogeneous and fine microstructure. 展开更多
关键词 亚共晶体 铝合金 电解作用 有色金属
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Synergistically Improved Mechanical Properties and Thermal Conductivity of Hypoeutectic AlSiNiFeMg Alloy Prepared by Ultrasonic-assisted Casting
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作者 ZHANG Wenda YUAN Xuan +4 位作者 ZHOU Yuli ZHONG Gu BAI Peikang WANG Hongfu LIU Jun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第6期1565-1568,共4页
We employed a melt ultrasonic treatment near the liquidus to prepare a high-thermal-conductivity Al-4Si-2Ni-0.8Fe-0.4Mg alloy.The influences of various ultrasonic powers on its microstructure,mechanical properties,and... We employed a melt ultrasonic treatment near the liquidus to prepare a high-thermal-conductivity Al-4Si-2Ni-0.8Fe-0.4Mg alloy.The influences of various ultrasonic powers on its microstructure,mechanical properties,and thermal conductivity were investigated.It is shown that near-liquidus ultrasonication significantly refines the alloy grains and eutectic structure,synergistically improving the alloy’s mechanical properties and thermal conductivity.Specifically,the grain size decreased by 84.5%from 941.4 to 186.2μm.Increasing the ultrasonic power improved the thermal conductivity of the alloy slightly and significantly enhanced its mechanical properties.At an ultrasonic power of 2100 W,the tensile strength,yield strength,elongation rate,and thermal conductivity were 216 MPa,142 MPa,6.3%,and 169 W/(m·k),respectively. 展开更多
关键词 al-si alloy mechanical property thermal conductivity ultrasonic treatment SOLIDIFICATION microstructure
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Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy
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作者 Wen-ning Liu Wei Zhang +6 位作者 Peng-yue Wang Yi-xian Liu Xiang-yi Jiao Ao-xiang Wan Cheng-gang Wang Guo-dong Tong Shou-mei Xiong 《China Foundry》 SCIE EI CAS CSCD 2024年第1期11-19,共9页
The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron mi... The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%). 展开更多
关键词 hypoeutectic al-si alloy high pressure die casting POROSITY externally solidified crystal tensile property
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Effect of combinative addition of mischmetal and titanium on the microstructure and mechanical properties of hypoeutectic Al-Si alloys used for brazing and/or welding consumables 被引量:2
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作者 王博 薛松柏 +1 位作者 王俭辛 林中强 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第2期193-202,共10页
Effects of mischmetal(RE) and/or Ti modifier on the microstructure including α-Al dendrites, eutectic Si phases and other secondary phases of Al-Si brazing and/or welding alloys were investigated by differential sc... Effects of mischmetal(RE) and/or Ti modifier on the microstructure including α-Al dendrites, eutectic Si phases and other secondary phases of Al-Si brazing and/or welding alloys were investigated by differential scanning calorimetry(DSC), optical microscopy(OM), scanning electron microscopy(SEM). The DSC results showed that an addition of RE decreased the eutectic temperature and caused supercooling, promoting the nucleation of eutectic Si crystals. In addition, the maximum temperature of the first endothermic peak varied with the different RE contents, which had a good correlation with the microstructural modification of the eutectic Si phase. The α-Al dendrites were well refined by increasing the cooling rate or adding 0.08 wt.% of Ti. When 0.05 wt.% RE was added to the Al-5Si-0.08 Ti alloy, the morphology of eutectic Si phase was transformed from coarse platelet to fine fibers and the mechanical properties of the resulting welding rod were well improved. Whereas, when excess RE was added, a large number of β-Fe phases appeared and the aspect ratios of β-Fe phases increased. The morphologies and chemical components of two kinds of RE-containing intermetallic compounds(IMCs) were also discussed. 展开更多
关键词 al-si alloy rare earths modification microstructure mechanical properties
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Microstructure Evolution of Hypoeutectic Al-Si Alloy With Electromagnetic Stirring and Ultrasonic Treatment
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作者 ZHANG Yu-bo FU Ying +2 位作者 WANG Tong-min CAO Zhi-qiang LI Ting-ju 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2012年第S1期212-216,共5页
Effects of electromagnetic stirring(EMS),ultrasonic treatment(UST)and the combination of EMS and UST(EU)on solidification structure were investigated in hypoeutectic A1-Si alloy.The results indicate that EMS,UST and E... Effects of electromagnetic stirring(EMS),ultrasonic treatment(UST)and the combination of EMS and UST(EU)on solidification structure were investigated in hypoeutectic A1-Si alloy.The results indicate that EMS,UST and EU can refine primary u-A1 and modify eutectic silicon by influencing their nucleation and growth processes.EMS can fracture the dendrite arms and lead to decrease of primary α-Al grain size.It also changes the morphology of eutectic silicon and widens the separation of silicon plates.For UST,the cavitation and acoustic streaming are the principal reasons for the microstructure refinement,which enhance the undercooled and heterogeneous nucleation.EU has combined the features of EMS and UST,hence obtains the best effect on the microstructure evolution.Significant refinement of primary α-Al and evident modification of eutectic silicon are observed with EU.In addition,the mechanism of morphological evolution with EU was preliminarily discussed. 展开更多
关键词 electromagnetic stirring ultrasonic treatment al-si alloy MICROSTRUCTURE
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Microstructure and room temperature mechanical properties of NiAl-Cr(Mo)-(Hf,Dy) hypoeutectic alloy prepared by injection casting 被引量:4
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作者 盛立远 杨芳 +2 位作者 奚廷斐 郑玉峰 郭建亭 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期983-990,共8页
The NiA1 Cr(Mo) (Hf, Dy) hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigat... The NiA1 Cr(Mo) (Hf, Dy) hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigated. The results reveal that with the addition of Hf and Dy, the Ni2AIHf Heusler phase and NisDy phase form along the NiAI/Cr(Mo) phase boundaries in intercellular region. By the injection casting method, some Ni2AIHf Heusler phase and NisDy phase transform into Hf and Dy solid solutions, respectively. Moreover, the microstructure of the alloy gets good optimization, which can be characterized by the fine interlamellar spacing, high proportion of eutectic cell area and homogeneously distributed fine Ni2AIHf, NisDy, Hf solid solution and Dy solid solutions. Compared with conventional-cast alloy, the room temperature mechanical properties of injection-cast alloy are improved obviously. 展开更多
关键词 NiAI based hypoeutectic alloy HF DY injection casting MICROSTRUCTURE mechanical properties
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Effect of mixing temperature on microstructure of an Al-Si alloy prepared by controlled diffusion solidification 被引量:1
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作者 Han Xue Ti-jun Chen +3 位作者 Xue-zheng Zhang Guang-li Bi Ying Ma Ren-guo Guan 《China Foundry》 SCIE CAS CSCD 2023年第3期241-252,共12页
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 pr... 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 calculation.The 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 rate.The nuclei grow up in nondendritic mode,resulting in spheroidal,at least,nondendritic grains.In 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 matched.Subsequent observation on casting microstructures shows that the employed simulation and calculation processes are reasonable and the achieved results are reliable. 展开更多
关键词 controlled diffusion solidification al-si alloy nucleation and growth SUPERCOOLING nondendritic grains
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Effects of magnesium and copper additions on tensile properties of Al-Si-Cr die casting alloy under as-cast and T5 conditions 被引量:1
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作者 Hong-yi Zhan Yi-wu Xu +3 位作者 Pan Wang Jian-feng Wang Jin-ping Li Le-peng Zhang 《China Foundry》 SCIE CAS CSCD 2023年第1期12-22,共11页
Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part consolidation.It also offers a higher design freedom for more mas... Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part consolidation.It also offers a higher design freedom for more mass-efficient thin-walled body structures.For body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product requirement.To enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical properties.Optimizing die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC components.The present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat treatment.It was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile ductility.Mg addition is very effective in improving strength and has minor impact on tensile ductility.The investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars. 展开更多
关键词 al-si alloy INTERMETALLICS high pressure die casting tensile property T7 heat treatment
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Effect of molybdenum on the microstructure and wear resistance of hypoeutectic Fe-Cr-B-C hardfacing alloys 被引量:4
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作者 Wang Shenglin Cui Li +2 位作者 He Dingyong Liu Hao Wang Xu 《China Welding》 EI CAS 2018年第4期46-51,共6页
Hypoeutectic Fe-Cr-B-C hardfacing alloys with different molybdenum( Mo) contents( The design content was 0,2,3. 3 and 4. 5 wt. %,respectively) were deposited using the flux-cored wire by means of metal active gas arc ... Hypoeutectic Fe-Cr-B-C hardfacing alloys with different molybdenum( Mo) contents( The design content was 0,2,3. 3 and 4. 5 wt. %,respectively) were deposited using the flux-cored wire by means of metal active gas arc welding. The effects of Mo on the refinement of microstructures,eutectic microstructure changes and improvement of wear resistance were investigated. The main results were shown as follows: the added Mo could increase the volume fraction of eutectic microstructure and reduce the size of coarse primary austenite as well as the volume fraction. The carboboride of M3( B,C) could be observed in hypoeutectic Fe-Cr-B-C hardfacing alloys at the Mo design content of ≤2. 0 wt. %,while that of M23( B,C)6was formed when 3. 3 wt. % Mo was added.Additionally,the wear resistance of alloys was increased with the increase in Mo content. Specifically,the highest wear resistance of alloys was achieved at 4. 5 wt. % Mo design content,which was 113. 7% higher than that in alloys without Mo. 展开更多
关键词 hypoeutectic hardfacing alloy MICROSTRUCTURE wear resistance MOLYBDENUM
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Effect of Sr modification on microstructure and thermal conductivity of hypoeutectic Al−Si alloys 被引量:17
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作者 Jun-qi GAN Yu-jian HUANG +1 位作者 Cheng WEN Jun DU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第11期2879-2890,共12页
Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al... Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable. 展开更多
关键词 hypoeutectic Al−Si alloy Sr modification eutectic Si morphology thermal conductivity Al/Si interface
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