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Interactions of particles with solidifying front in Al_2O_(3P) /Al Si composites

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中国有色金属学会会刊：英文版 1999年第3期9卷 524-529页

作者： Wu Shusen(吴树森), huang naiyu(黄乃瑜),An Ping(安萍) College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P.R. China Huazhong Univ Sci & Technol Coll Mat Sci & Engn Wuhan 430074 Peoples R China

The behavior of ceramic particles at the solid/liquid interface and the distribution of particles in metallic matrix composites was studied with a zone unidirectional solidification method. Two kinds of partice dispersed composites, Al 2O 3P /Al 12.6%Si Sr and Al 2O 3P /Al 12.6%Si Sr Ca containing Al 2O 3 particles in volume fraction 2%～5% were used. In the Al 2O 3P /Al Si Sr composites, the particles were pushed by the solidifying front, and did not uniformly distribute in the solid. But in the Al 2O 3P /Al Si Sr Ca composites, the particles were engulfed by the solidifying front and uniformly distributed in the solid. The particles engulfing into the solid was realized only by Sr and Ca addition at the same time. As the interfacial energy between solid and particle was decreased in this case, the Al 2O 3 particles acted as the substrates of heterogeneous nucleation for the Si phases, which made the particles to be engulfed.

关键词： metallic matrix composites solidification particle size distributionDocument code: A

Newly developed vacuum differential pressure casting of thin-walled complicated Al-alloy castings

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China Foundry 2005年第2期2卷 102-107页

作者： Xuanpu DONG naiyu huang Shushen WU School of Material Science and Engineering Hua Zhong University of Science and Technology Wuhan 430074 HubeiP. R. China

The newly designed vacuum differential pressure casting (VDPC) unit was introduced, by which the capabilityof the VDPC process to produce thin-walled complicated Al-alloy castings, that are free from oxides, gas pore andshrinkage cavity and thus enhance overall part quality, was studied. Experimental results were compared with those oftraditional gravity pouring and vacuum suction casting. The first series of experiments were focused on investigating thecastability of thin section Al-alloy casting. In the second series of experiments the metallographic evidence, castingstrength and soundness were examined. Finally, case studies of very interesting thin walled complicated casting applicationswere described. The advantages of the described technique have made possible to produce thin walled complicatedAl-alloy casting (up to a section thickness of 1 mm), which is not practical for gravity pouring and vacuum suction casting.

关键词： vacuum differential pressure casting complicated thin walled castings counter gravity casting

Dry reusing and wet reclaiming of used sodium silicate sand

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China Foundry 2005年第1期2卷 38-43页

作者： Zitian FAN naiyu huang Huafang WANG Xuanpu DONG School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074Hubei P. R. China

Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitable technique for the used sand. When the recycled sand is used as support sand, the used sand is only reused by dry process including breaking, screening, dust-removal, etc., and it is not necessary that the used sand is reclaimed with strongly rubbing and scraping method, but when the recycled sand is used as facing sand (or single sand), the used sand must be reclaimed by wet method for higher removal rate of the residual binders. The characteristics and the properties of the dry reused sand are compared with the wet reclaimed sand after combining the different use requirements of support sand and facing sand (or single sand), and above the most adaptive scheme has also been validated.

关键词： used sodium silicate sand dry reusing wet reclaiming

铸件轻量化、精确化的新进展——第63届世界铸造会议特种铸造及有色合金论文综述

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特种铸造及有色合金 1999年第1期19卷 50-52页

作者：黄乃瑜华中理工大学

介绍了第６３届世界铸造会议特铸和有色合金论文的主要内容及在铸件轻量化、精确化方面取得的最新成果，包括进一步扩大铝、镁合金应用领域；提高铸件质量的新经验；加速开发适用于铝、镁合金特点的精确成形技术的新进展；以及欧洲工业... 详细信息

介绍了第６３届世界铸造会议特铸和有色合金论文的主要内容及在铸件轻量化、精确化方面取得的最新成果，包括进一步扩大铝、镁合金应用领域；提高铸件质量的新经验；加速开发适用于铝、镁合金特点的精确成形技术的新进展；以及欧洲工业发达国家加快开发镁合金成套技术的新动向。

关键词：镁合金精确成形铝合金会议铸件轻量化

Investigating on casting mold (or core) making with coated sand by the selected laser sintering

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China Foundry 2004年第2期1卷 122-126页

作者： Zitian FAN naiyu huang Yan LI Zhili LIU State Key Laboratory of Plastic Simulation and Die&Mold Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiP.R.China

Using a special coated sand as the material of the selected laser sintering (SLS), the authors test and investigate the strength change of the test samples in terms of different sintering parameters (scanning speed, laser power, sintering thickness, and so on). The characteristics of coated sand hardening by laser beam are analyzed. The sintered mold (or core) for given casting is poured with molten metal.

关键词： rapid prototyping selected laser sintering(SLS) laser scanning casting mold(core) technological parameters

熔体混合处理消失模铸造AZ91合金组织及性能研究

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特种铸造及有色合金 2007年第12期27卷 954-956页

作者：田学锋樊自田黄乃瑜东北大学材料与冶金学院华中科技大学材料科学与工程学院

采用熔体混合处理技术对AZ91合金在消失模铸造条件下的组织形貌和力学性能作了研究,结果表明,熔体混合处理能够细化AZ91的组织,并显著提高力学性能(当混合温度为720℃时抗拉强度比不细化时提高24%),其效果强于传统的熔体高温处理。熔体... 详细信息

采用熔体混合处理技术对AZ91合金在消失模铸造条件下的组织形貌和力学性能作了研究,结果表明,熔体混合处理能够细化AZ91的组织,并显著提高力学性能(当混合温度为720℃时抗拉强度比不细化时提高24%),其效果强于传统的熔体高温处理。熔体混合处理通过在混合液体中产生更多的核胚以增加形核,来细化枝晶组织。

关键词：熔体混合处理消失模铸造镁合金微观组织力学性能

Rapid precision casting for complex thin-walled aluminum alloy parts

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China Foundry 2004年第2期1卷 117-121页

作者： Xuanpu DONG naiyu huang Zitian FAN Hongjun LIU School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074HubeiP.R.China

Based on Vacuum Differential Pressure Casting (VDPC) precision forming technology and the Selective Laser Sintering (SLS) Rapid Prototyping (RP) technology, a rapid manufacturing method called Rapid Precision Casting (RPC) process from computer three-dimensional solid models to metallic parts was investigated. The experimental results showed that the main advantage of RPC was not only its ability to cast higher internal quality and more accurate complex thin-walled aluminum alloy parts, but also the greatly-reduced lead time cycle from Selective Laser Sintering (SLS) plastic prototyping to metallic parts. The key forming technology of RPC for complex thin-walled metallic parts has been developed for new casting production and Rapid Tooling (RT), and it is possible to rapidly manufacture high-quality and accurate metallic parts by means of RP in foundry industry.

关键词： vacuum differential pressure casting selective laser sintering precision casting rapid prototyping technology

Accuracy analysis of the part made by selected laser sintering

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China Foundry 2004年第1期1卷 49-52页

作者： Zitian FAN naiyu huang Yuejia XIAO Ming HAN State Key Laboratory of Plastic Simulation and Die & Mold Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 Hubei P.R. China

The effects of different factors, including the precision of selected laser sintering (SLS) equipment, sintering temperature, sintered thickness of individual layer and laser scanning route, on the SLS part accuracy h... 详细信息

关键词： rapid prototyping selected laser sintering laser scanning part accuracy

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负压消失模工艺中EPS热解产物的研究

特种铸造及有色合金 2000年第4期20卷 22-24页

作者：杨家宽黄乃瑜李焰华中科技大学

消失模铸造工艺中EPS热解过程及热解产物的组成一直是消失模工艺研究的热点之一。采用气相色谱法对负压消失模工艺型腔中EPS热解产物样品进行了分析 ,并且考察了合金浇注温度、负压度以及涂层透气性对热解产物组成的影响。试验结果表明 ... 详细信息

消失模铸造工艺中EPS热解过程及热解产物的组成一直是消失模工艺研究的热点之一。采用气相色谱法对负压消失模工艺型腔中EPS热解产物样品进行了分析 ,并且考察了合金浇注温度、负压度以及涂层透气性对热解产物组成的影响。试验结果表明 ,浇注温度对EPS热解产物的组成以及EPS在型腔中的发气量有着决定性的影响 ,从而影响金属液流动前沿的形态 ;随着负压度和涂层透气性的增加 ,EPS热解产物能够更快地排出型腔 ,在高温区停留的时间减少 ,EPS发气量降低。

关键词：消失模铸造发泡聚苯乙烯气相色谱法流动形态