Jiuzhou ZHAO
,
L.Ratke
,
Jun JIA
,
Qingchun LI
材料科学技术（英文）
The microstructure development during a cooling period of alloys being immiscible in the liquid state such as Al-Pb or Al-Bi has gained renewed scientific and technical interest during the last decades. Experiments have been performed to investigate the phase transformation kinetics in the liquid miscibility gap and numerical models have been developed to simulate and analyze the solidification process. The recently developed computational modeling techniques can, to some extent, be applied to describe the decomposition, the spatial phase separation and the microstructure evolution during a cooling period of an immiscible alloy through the miscibility gap. This article overviews the researches in this field.
关键词:
Immiscible alloy
,
null
,
null
,
null
Jun SHEN
,
Zhuangde XIE
,
Bide ZHOU
,
Qingchun LI
,
Zhijun SU
,
Hongsheng LE
材料科学技术（英文）
A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the alloy was very fine and its microstructure was mainly consisted of Si crystals plus intermetallic compound A19FeSi3, which were very fine and uniformly distributed.
关键词:
Jianfei SUN
,
Jun SHEN
,
Fuyang CAO
,
Qingchun LI
材料科学技术（英文）
In this paper, the behaviors of nucleation and growth of atomizing droplets were investigated by means of microstructure observation and theoretical analysis. The results showed that, there is a unique heterogeneous nucleation mechanism for atomizing process that pre-solid smaller particles colliding with and embedding in liquid-state larger ones act as heterogeneous nuclei. In addition, the reasons of presenting the dendritic growth was analyzed based on the nonequilibrium solute distribution theory, and the relationship between the microstructural refinement and the cooling rate of the material was given.
关键词:
Manchang GUI
,
Jun JIA
,
Guangsheng SONG
,
Qingchun LI
材料科学技术（英文）
Hypo- and hyper-eutectic Al-Si alloys were rapidly solidified from the low or high temperature melt using water quenching and melt-spinning technique. The differences in microstructure of rapid solidification alloys were studied by scanning and transmission electron microscopy, and X-ray diffraction methods. The primary silicon in the Al-22(wt pct)Si alloy quenched in room temperature water from high temperature melt was smaller than that quenched from low temperature melt. Compared with the ribbons spun from low temperature melt, the ribbons spun from high temperature melt had finer Al-rich and Si-rich phase particles in either Al-7(wt pct)Si or Al-18(wt pct)Si alloy. The mechanism was explained by the nature of the liquid structure.
关键词:
Chengsong CUI
,
Zhenyu LI
,
Fuyang CAO
,
Qingchun LI
材料科学技术（英文）
A shape modeling of spray formed composite roll, which is utilized to predict the shape and dimension of roll during spray forming process, is developed in this paper. The influences of the principal spray forming parameters, such as the spatial distribution of melt mass flux, spray distance, rotating and translating speeds of substrate bar etc., on the geometry and dimension of spray formed product were investigated.
关键词:
Chengsong CUI
,
Fuyang CAO
,
Zhenyu LI
,
Qingchun LI
材料科学技术（英文）
Modeling of heat transfer and solidification of composite roll was established and used to predict the thermal history and solidification process of roll during spray forming. Evolution of temperature field of the preform and cooling rate in the growing deposit during spray deposition and post-deposition were numerically simulated.
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