Structure of undercooled Ni-Sn eutectic
01 May 1970-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science (Springer New York)-Vol. 1, Iss: 5, pp 1449-1451
About: This article is published in Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science.The article was published on 1970-05-01. It has received 81 citations till now. The article focuses on the topics: Eutectic system.
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TL;DR: In this paper, the authors focus on measurements and theories pertaining to homogeneous nucleation under cooled liquids and glasses that transform to phases of the same composition, and incorporate time-dependent nucleation and the interface kinetics into the field-theoretic approaches to give theories that are as widely applicable and, hence, testable as the classical theory.
Abstract: Publisher Summary This chapter focuses on measurements and theories pertaining to homogeneous nucleation under cooled liquids and glasses that transform to phases of the same composition. The dynamical model describing the cluster evolution appears to be quantitatively correct. Although there are some experimental and theoretical difficulties with the classical theory, there are also many approaches to rectify these problems. At present, there are no experiments that can demonstrate or can refute conclusively the validity of the classical theory in the regime where it is expected to be valid. This is partially because of a lack of knowledge of the correct values for the parameters that are fit by the theory. Better measurements of the steady-state and time-dependent nucleation rates and the free-energy difference as a function of temperature, and the design of new experiments such as the multistep annealing treatments discussed in the chapter are used to test more rigorously nucleation theories. Time-dependent nucleation and the interface kinetics are incorporated into the field-theoretic approaches to give theories that are as widely applicable and, hence, testable as the classical theory.
674 citations
TL;DR: The study of metallic melts, their physical properties, and their solidification behavior is of relevance to understanding of fundamental principles and to metallurgical applications as discussed by the authors, and many, if not all, of them have been studied.
Abstract: The study of metallic melts, their physical properties, and their solidification behaviour is of relevance to understanding of fundamental principles and to metallurgical applications. Many, if not...
307 citations
TL;DR: Undercooling at crystal nucleation onset of liquid Ge droplets is measured and microstructures of the droplets are examined in this paper, where undercooling values ranging from 150-415 + or 20 C were obtained.
102 citations
TL;DR: In this article, a comparison is made between high speed cinematography and optical temperature measurements of the solidification of an undercooled Ni-25 wt pct Sn alloy, and it is concluded that the coarse structure observed comprises an array of much finer, solute-controlled dendrites.
Abstract: A comparison is made between high speed cinematography and optical temperature measurements of the solidification of an undercooled Ni-25 wt pct Sn alloy The first part of this study notes that solidification during the recalescence period at all undercoolings studied occurred in the form of a dendritelike front moving across the sample surface, and that the growth velocities observed agree with calculation results for the dendrite growth model of Lipton et al (1986); it is concluded that the coarse structure observed comprises an array of much finer, solute-controlled dendrites In the second part, attention is given to the solidification of levitated metal samples within a transparent glass medium for the cases of two undercooled Ni-Sn alloys, one of which is eutectic and another hypoeutectic The data obtained suggest a solidification model involving dendrites of very fine structure growing into the melt at temperatures near the bulk undercooling temperature
99 citations
TL;DR: In this article, the authors applied the electromagnetic levitation technique to crystallize containerlessly bulk melts of eutectic Ni-Si, Co-Sb and Ni-Al-Ti alloys at various undercoolings and cooling rates.
87 citations