材料期刊网

Prediction of Endpoint Phosphorus Content of Molten Steel in BOF Using Weighted K-Means and GMDH Neural Network

WANG Hong-bing , XU An-jun , AI Li-xiang , TIAN Nai-yuan

钢铁研究学报(英文版)

The hybrid method composed of clustering and predicting stages is proposed to predict the endpoint phosphorus content of molten steel in BOF (Basic Oxygen Furnace). At the clustering stage, the weighted K-means is performed to generate some clusters with homogeneous data. The weights of factors influencing the target are calculated using EWM (Entropy Weight Method). At the predicting stage, one GMDH (Group Method of Data Handling) polynomial neural network is built for each cluster. And the predictive results from all the GMDH polynomial neural networks are integrated into a whole to be the result for the hybrid method. The hybrid method, GMDH polynomial neural network and BP neural network are employed for a comparison. The results show that the proposed hybrid method is effective in predicting the endpoint phosphorus content of molten steel in BOF. Furthermore, the hybrid method outperforms BP neural network and GMDH polynomial neural network.

关键词: basic oxygen furnace , endpoint phosphorus content , K-means , neural network , GMDH

Formation of PFZ and Its Effect in a RSP AI-Li Alloy

Liang ZHEN Yuexian CUI Dezhuang YANG Department of Materials Science , Harbin Institute of Technology , Harbin , 150006 , ChinaShenglong DAI Guifu YU Beijing Institute of Aeronautical Materials , Beijing 100095 , China

材料科学技术（英文）

The formation of precipitation free zone (PFZ) and its effect in a RSP AI-Li alloy has been studied. The results show that PFZ is easy to form when aged at 190℃,but there is no equilibrium phase on grain boundaries.The growth of PFZ in the alloy is different from that in conventional AI-Li alloys, The effect of PFZ is of great importance because of its large volume fraction in the alloy.It offsets the beneficial effect of RSP,and is thought to be an important factor that leads to the poor toughness and low ductility of RSP AI-Li alloy sheet.

关键词: precipitation free zone , null , null , null

SUPERPLASTICITY OF A RAPIDLY SOLIDIFIED AI-Li ALLOY

MANG Weishi WANG Guozhi ZHANG Yongchang HU Zhuangqi SHI Changxu Institute of Metal Research , Academia Sinica , Shenyang , China Yongchang Associate Professor , Institute of Metal Research , Academia Sinica , Shenyang 110015 , China

金属学报(英文版)

A rapidly solidified microcrystalline Al-Li-Cu-Mg-Zr alloy and its superplasicity have been investigated.An optimum tensile elongation of 585% was obtained at 540℃ and strain rate 1.67×10~(-2)s~(-1).The superplastic Al-Li alloy is manufaetured using thermomechanical pro- cessing:solution,overaging,warm rolling and recrystallization.Microstructural changes in thermomechanical processing and cavitation occurred during superplastic deformation have been observed.The superplastic failure of alloy may be caused mainly by nucleation and growth of cavities as well as the linkage around grains.

关键词: superplasticity , null , null , null

Nucleation and Formation of Stable and Metastable Phases in Undercooled AI-Li Melts

Shenglong DAI Guifu YU Minggao YAN Institute of Aeronautical Materials , Beijing , 100095 , China

材料科学技术（英文）

A modified nucleation and competitive growth kinetic theory considering unsteady nucleation and effect of composition in dilute binary alloys was suggested,based on which the selections of δ.δ' and α phases in undercooled Al-Li melts were summarized by both isothermal and continuous cool- ing treatment methods.

关键词: undercooling , null , null

MECHANICAL PROPERTIES OF Al-Li ALLOY 8090 AT CRYOGENIC TEMPERATURES

SUN Dongsheng LI Fengzhao ZHANG Gang Shandong Polytechnic University , Jinan , China Lecturer , Centre of Materials Testing and Analysis , Shandong Polytechnic University , Jinan 250014 , China

金属学报(英文版)

Cryogenic strength,ductility and toughness of AI-Li alloy 8090 were found to be superior to those at ambient temperature,and up to optima at about 20 K.Different aging regimes may only influence on its cryogenic yield strength and elongation.

关键词: Al-Li alloy , null , null , null

DETERMINATION OF ACTIVITY OF AI IN SOLID Cu-Al ALLOYS

ZHANG Qianxiang , University of Science and Technologys Beijing , Beijing , China

金属学报(英文版)

Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by meansof solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 ZrO_2·Y_2O_3 Ni, NiOand Al(a_1, in alloy), Al_2O_3 Na, βAl_2O_3 Al(a_2 , in alloy), Al_2O_3

关键词: Cu-Al alloy , null , null , null , null

Precipitation of 8090 AI-Li Alloy during Overaging and Its Influence on the Recrystallization

LIU Yulin ZHANG Yun ZHAO Hong'en HU Zhuangqi SHI Changxu ** Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China+ To whom correspondence should be addressed.

材料科学技术（英文）

关键词: Al-Li alloy , null , null , null

EFFECTS OF DIFFUSION WELDING PARAMETERS ON JOINT STRENGTH OF SiCw/6061AI COMPOSITE

L.M. Liu , J.T. Niu , Z.H. Lai , Y.L. Guo and J.P. Zhai (National Key Laboratory of Advanced Welding Production Technologyt HIT , Harbin 150001 , China)

金属学报(英文版)

Diffusion welding was used to join SiCw/6061AI composites. The effects of welding pammeters on strength Of welded joint were investigated. JOint Of high quality for SiCw/6061Al composites can be obtained with aPPropriate diffesion welding parameters.

关键词: diffusion welding , null

Thermal Analysis of Precipitate Dissolution in Binary Al-Li Alloy

YAO Daping HU Zhuangqi LI Yiyi ZHANG Yun and SHI Changxu Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China.

材料科学技术（英文）

In this paper,the activation energy for precipi- tate dissolution in binary AI-Li alloy has been in- vestigated by considering precipitate dissolution in Al-Li alloy,continuously heated as a thermally ac- tivated process.The proposed calculation was car- ried out by changing the scanning rate in DSC measurement.The results show that the formation of GP zone is easy because the activation energy for its dissolution is smaller than that for Li atom diffu- sion in the matrix.The δ′dissolution consists of two steps:the first step needs larger thermal activation to break down the superlattice structure,and the second is much easier like GP zone dissolution.The phase is the most stable,which needs much larger thermal activation to disappear.

关键词: Al-Li alloy , null , null , null

Effect of Li and Ti Additions on L■α(Al)+Mg_2Si Pseudobinary Eutectic Reaction

Shengxu ZHAO , Shunpu LI , Deqian ZHAO , Mingxiang PAN and Xichen CHEN(Institute of Physics , Chinese Academy of Sciences , Beijing 100080 , China)

材料科学技术（英文）

Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.

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