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Effect of primary phase structure on the undercoolability of quasicrystal-forming melt

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Progress in Natural Science:Materials International 2002年第4期 79-82页

作者： LIU Xinbao , YANG Gencang, FAN Jianfeng and SONG Guangsheng(State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China) State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China

The relationship between α and △Trel is investigated, where α is a factor that depends on the structure of primary phase and △Trel, the relative undercooling of melt. A linear relationship between α and the relat... 详细信息

关键词： primary phase quasicrystals short-range order (SRO).

Regulating microstructures and mechanical properties of Al-Fe-Ni alloys

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Progress in Natural Science:Materials International 2020年第1期30卷 54-62页

作者： Zeyu Bian Yingtao Liu Shihan Dai Zhe Chen Mingliang Wang Dong Chen Haowei Wang School of Materials Science & Engineering Shanghai Jiao Tong University State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Anhui Aluminium Matrix Composites Engineering Research Centre

Mechanical properties of Al-Fe-Ni eutectic alloys have been investigated based on the nominal mass fraction of eutectic phase,and the added Fe/Ni mass *** X-Ray diffraction,scanning electron microscopy equipped with energy dispersive spectroscopy and transmission electron microscope have been used to identify phase composition,characterize microstructure and crystal structure of Al9FeNi phase,*** results demonstrate that the nominal mass fraction of eutectic phase control the presence of primary *** tensile strength slightly increases,and the ductility deteriorates sharply as the volume fraction of primary phase *** Fe/Ni mass ratio has the profound effect on the microstructures(i.e.,size and shape) of primary *** the Fe/Ni ratio is approaching to 1,the primary phase becomes rod-like shape,which can enhance the ductility of alloys over the flake-like *** increasing cooling rate can effectively reduce the eutectic grains size and primary phase fraction,and further significantly improve mechanical properties of the alloys.

关键词： Al-Fe-Ni eutectic alloys Microstructures primary phase High-temperature alloys

Influence of clusters in melt on the subsequent glass-formation and crystallization of Fe–Si–B metallic glasses

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Progress in Natural Science:Materials International 2015年第2期25卷 137-140页

作者： Shaoxiong Zhou Bangshao Dong Rui Xiang Guangqiang Zhang Jingyu Qin Xiufang Bian Advanced Technology & Materials Co. Ltd. Central Iron & Steel Research Institute Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University

The liquid structure of seven representative Fe–Si–B alloys has been investigated by ab initio molecular dynamics simulation focusing on the role of clusters in terms of glass-forming ability(GFA) and crystallization. It is demonstrated that the type of primary phase precipitated from amorphous state under heat treatment is determined by the relative fraction and role of various clusters in melt. The alloy melt shows higher stability and resultantly larger GFA when there is no dominant cluster or several clusters coexist, which explains the different GFAs and crystallization processes at various ratios of Si and B in the Fe–Si–B system. The close correlation among clusters, crystalline phase and GFA is also studied.

关键词： Metallic glasses Clusters Glass-forming ability primary phase ab initio molecular dynamics

Influences of electric pulse on solidification structure of LM-29 Al-Si alloy

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China Foundry 2010年第2期7卷 153-156页

作者： He Lijia Wang Jianzhong Qi Jingang Du Huiling Zhao Zuofu College of Material Science and Engineering Liaoning University of Technology Jinzhou 121001 China

The metallographic structure of LM-29 aluminum-silicon alloy modified by electric pulse treatment has been investigated and compared with those *** solidification structure of LM-29 alloy has been analyzed by means of M1AP3 Quantimet image processing and analysis system,and then the solidification process has been analyzed by means of differential scanning calorimetry(DSC).The results indicate that the primary silicon phase was refined remarkably by electric pulse while the tensile strength and elongation properties increased *** pulse treatment can also increase the binding power between silicon clusters and alloy melt matrix,as a result,the precipitation of primary silicon phase is suppressed to meet the demand of supercooling degree for nucleating,*** electric pulse modification has great influence on the size of silicon atomic cluster as well as its distribution in the melt,subsequently,leads to the refinement of solidification structure.

关键词： electric pulse modification LM-29 alloy primary phase cluster

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Microstructure evolution of directionally solidifi ed Sn-16%Sb hyperperitectic alloy

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China Foundry 2008年第3期5卷 167-171页

作者： Hu Xiaowu Li Shuangming Liu Lin Fu Hengzhi State Key Laboratory of Solidification Processes Northwestern Polytechnic University Xi＇an 710072 Shaanxi China

The directionally solidified microstructure of Sn-16%Sb hyperperitectic alloy has been investigated at various solidification rates using a high-thermal gradient directional solidification apparatus. The results indicate that the solidification microstructure consists of hard primary intermetallic SnSb phase embedded in a matrix of soft peritectic ,8-Sn phase. The primary SnSb phase exhibits faceted growth with tetragonal or trigonal shapes. At the same time, the primary SnSb phase is refined with an increase in the solidification rate and dispersed more uniformly in the matrix of,8-Sn phase. The volume fraction of the SnSb phase firstly decreases and then increases when the solidification rate increases in directional solidification of Sn-16%Sb hyperperitectic alloy.

关键词： Sn-16%Sb hyperperitectic alloy directional solidification primary phase morphological size volume fraction

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Growth morphology of Ni3Si in high undercooled Ni-Si eutectic alloy

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Progress in Natural Science:Materials International 1997年第5期 114-121页

作者：惠增哲杨根仓周尧和 China Northwestern Polytechnical University State Key Laboratory of Solidification Processing Xi’an 710072

Ni-Si eutectic alloy has been undercooled up to 224 K by means of combination of molten-glass denu-cleation and cyclic superheating and cooling. The formation mechanism of rapidly solidified microstructures and growth morphology of the faceted phase Ni3Si have been studied. Under undercooling condition, the two primary phases forming the eutectic often appear before eutectic formation. With the increase of undercooling, the growth morphology of Ni3Si transits from the faceted phase to the non-faceted phase. The critical undercooling of the transition is approximately 60 K.

关键词： high undercooling eutectic alloy primary phase growth morphology.