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Title: Pore nucleation in solidifying high-purity copper

Abstract

High-purity copper (6 or 7 N) was melted and solidified unidirectionally in the atmosphere of a H{sub 2}-Ar gas mixture for the purpose of studying the mechanism of pore nucleation in solidifying metal. Hydrogen content in the melt was controlled by changing the partial pressure in the atmosphere. Pores were formed when the hydrogen partial pressure in the atmosphere was 0.3 atm or more. Oxides of aluminum and silicon were observed at the bottom of the pores and the pores were nucleated heterogeneously. Water vapor with a very low partial pressure existed in the furnace atmosphere, and the melt must have contained a small amount of oxygen in equilibrium with this water vapor. The solid/liquid (S/L) interface was planar and convection was eliminated. The redistribution of the solute during solidification can, therefore, be estimated. The concentration of oxygen in the liquid at the S/L interface is estimated to be much larger than its initial concentration, due to the very small equilibrium distribution coefficient of oxygen in copper, and aluminum and silicon were oxidized even though their concentrations were very low. The probability of homogeneous nucleation by {alpha} particles was very small in these experiments.

Authors:
 [1]
  1. Waseda Univ., Tokyo (Japan). Dept. of Materials Science and Engineering
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
684462
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 30; Journal Issue: 9; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SOLIDIFICATION; COPPER; LIQUID METALS; HYDROGEN; ARGON; POROSITY; NUCLEATION; PRESSURE DEPENDENCE; OXYGEN

Citation Formats

Kato, Eiichi. Pore nucleation in solidifying high-purity copper. United States: N. p., 1999. Web. doi:10.1007/s11661-999-0253-z.
Kato, Eiichi. Pore nucleation in solidifying high-purity copper. United States. doi:10.1007/s11661-999-0253-z.
Kato, Eiichi. Wed . "Pore nucleation in solidifying high-purity copper". United States. doi:10.1007/s11661-999-0253-z.
@article{osti_684462,
title = {Pore nucleation in solidifying high-purity copper},
author = {Kato, Eiichi},
abstractNote = {High-purity copper (6 or 7 N) was melted and solidified unidirectionally in the atmosphere of a H{sub 2}-Ar gas mixture for the purpose of studying the mechanism of pore nucleation in solidifying metal. Hydrogen content in the melt was controlled by changing the partial pressure in the atmosphere. Pores were formed when the hydrogen partial pressure in the atmosphere was 0.3 atm or more. Oxides of aluminum and silicon were observed at the bottom of the pores and the pores were nucleated heterogeneously. Water vapor with a very low partial pressure existed in the furnace atmosphere, and the melt must have contained a small amount of oxygen in equilibrium with this water vapor. The solid/liquid (S/L) interface was planar and convection was eliminated. The redistribution of the solute during solidification can, therefore, be estimated. The concentration of oxygen in the liquid at the S/L interface is estimated to be much larger than its initial concentration, due to the very small equilibrium distribution coefficient of oxygen in copper, and aluminum and silicon were oxidized even though their concentrations were very low. The probability of homogeneous nucleation by {alpha} particles was very small in these experiments.},
doi = {10.1007/s11661-999-0253-z},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
number = 9,
volume = 30,
place = {United States},
year = {1999},
month = {9}
}