Microstructure Evolution of Directionally Solidified Al-25at.%Ni Peritectic Alloy

Microstructure evolution of peritectic Al-25at.%Ni alloy during directional solidification with pulling velocity ranging from 2 to 500m/s is investigated. The directional solidified alloy is composed of Al3Ni2, Al3Ni phase and eutectic (Al3Ni+Al) phase. When pulling velocity ranges from 2 to 5m/s, Al3Ni phase grows into an integral matrix. Majority of primary Al3Ni2 is consumed by peritecti reaction and transformation behind the peritectic interface with pulling velocity ranging from 2 to 20 m/s. While pulling rate increases, major Al3Ni phase direct solidifies from liquid. With cooling rate increasing, Al3Ni2 phase content firstly decreases and then increases, while the Al3Ni phase content decreases throughout.

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Microstructure evolution of peritectic Al–18 at.% Ni alloy directionally solidified in high magnetic fields

Journal of Material Science and Technology ◽

10.1016/j.jmst.2020.11.004 ◽

2021 ◽

Vol 76 ◽

pp. 51-59

Author(s):

Yubao Xiao ◽

Tie Liu ◽

Yuxin Tong ◽

Meng Dong ◽

Jinshan Li ◽

...

Keyword(s):

Magnetic Fields ◽

Microstructure Evolution ◽

High Magnetic Fields ◽

Directionally Solidified ◽

Ni Alloy

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Thermal Parameters, Tertiary Dendritic Growth and Microhardness of Directionally Solidified Al-3wt%Cu Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.452 ◽

2016 ◽

Vol 869 ◽

pp. 452-457 ◽

Cited By ~ 3

Author(s):

André Santos Barros ◽

Maria Adrina Paixão de Souza da Silva ◽

Otávio Fernandes Lima da Rocha ◽

Antonio Luciano Seabra Moreira

Keyword(s):

Growth Rate ◽

Directional Solidification ◽

Cooling Rate ◽

Dendritic Growth ◽

Solidification Process ◽

Flow Conditions ◽

Directionally Solidified ◽

Cu Alloy ◽

Cu Alloys ◽

Transient Heat Flow

The main purpose of this paper is to evaluate both tertiary dendritic arm growth and microhardness of Al-3wt%Cu alloy during horizontal directional solidification under transient heat flow conditions. Experimental thermal profiles recorded during solidification process allowed to determine growth rate and cooling rate values which are associated with both tertiary dendritic arm spacings and microhardness. The results show that initial tertiary branches growth only occurs when a cooling rate value of 1.14 K/s is reached. Variation of tertiary spacings is expressed as-1.1 and-0.55 power law functions of growth rate and cooling rate, respectively. A comparative analysis with other studies published in the literature that analyze tertiary dendritic growth of Al-Cu alloys considering transient directional solidification is carried out. Dependence of microhardness on dendritic arrangement is evaluated by experimental laws of power and Hall-Petch types with a view to permitting the applicability of the resulting expressions.

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Microstructure Evolution and Macro Segregation of Directionally Solidified Hypoeutectic and Hypereutectic Lead-Tin Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.895.3 ◽

2017 ◽

Vol 895 ◽

pp. 3-7

Author(s):

K.V. Sreenivas Rao ◽

N. Akhil

Keyword(s):

Growth Rate ◽

Directional Solidification ◽

Microstructure Evolution ◽

Solidification Rate ◽

Unidirectional Solidification ◽

Directionally Solidified ◽

Tin Alloys ◽

Alloy Increase ◽

Set Up ◽

Tin Content

Unidirectional solidification is preferred to multidirectional solidification for growing crystals in a particular direction. An experimental set-up consisting of Bridgman type of upward directional solidification was employed for the present investigation. The main aim of the present investigation was to assess the effect of unidirectional upward solidification on the segregation of off-eutectic Pb-Sn alloys at different translational speeds of the experimental set-up. Solidification experiments were conducted on hypoeutectic and hypereutectic Lead-Tin alloys. Different combinations of growth rate V and composition Co. were used to investigate their effect on longitudinal macro segregation. Macro segregation along the length of the samples was observed in hypoeutectic Pb-Sn alloys whereas no such macro segregation was observed in hypereutectic alloys. The intensity of longitudinal macro segregation was found to increase with the increase in initial tin content of the alloy, increase in distance from the chill end and decrease in the solidification rate.

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The effect of back-melting on the continuity of crystallographic orientation and composition in HgZnTe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133114 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1696-1697

Author(s):

H.J. Zuo ◽

M.W. Price ◽

R.D. Griffin ◽

R.A. Andrews ◽

G.M. Janowski

Keyword(s):

Directional Solidification ◽

Space Shuttle ◽

Solidification Process ◽

Space Experiment ◽

Infrared Detection ◽

Directionally Solidified ◽

Crystallographic Defects ◽

Semiconducting Alloys ◽

Uniform Composition ◽

Growth Experiments

The II-VI semiconducting alloys, such as mercury zinc telluride (MZT), have become the materials of choice for numerous infrared detection applications. However, compositional inhomogeneities and crystallographic imperfections adversly affect the performance of MZT infrared detectors. One source of imperfections in MZT is gravity-induced convection during directional solidification. Crystal growth experiments conducted in space should minimize gravity-induced convection and thereby the density of related crystallographic defects. The limited amount of time available during Space Shuttle experiments and the need for a sample of uniform composition requires the elimination of the initial composition transient which occurs in directionally solidified alloys. One method of eluding this initial transient involves directionally solidifying a portion of the sample and then quenching the remainder prior to the space experiment. During the space experiment, the MZT sample is back-melted to exactly the point at which directional solidification was stopped on earth. The directional solidification process then continues.

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