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Structure and Properties of Cast Near-Congruent Copper-Manganese Alloys

Authors :
K.J. Chaput
Kevin P. Trumble
Source :
Metallurgical and Materials Transactions B. 45:1793-1803
Publication Year :
2014
Publisher :
Springer Science and Business Media LLC, 2014.

Abstract

Microstructure development in the casting of copper-manganese alloys based on the congruent point at 34.6 wt pct Mn and 1146 K (873 °C) has been studied. The alloys were prepared by induction melting of electrolytic Cu and Mn in clay-graphite crucibles in open air. Under conventional casting conditions, the alloys exhibit fine cellular (non-dendritic) solidification morphology with a distinct absence of solidification shrinkage microporosity, and they maintain these attributes over a composition range of approximately 3 wt pct Mn about the congruent point. The high Mn concentration in the alloy admits carbon into solution in the melt, resulting in formation of manganese carbide Mn7C3 particles having two different forms (globular and angular) in the cast microstructure. The Mn carbide was eliminated or controlled to low levels by melting in an alumina or a silicon carbide crucible, or in a clay-graphite crucible at lower temperatures. Microstructure development in casting the alloy was analyzed in terms of the available phase diagrams and thermochemical data. Hardness and tensile testing indicated a potent solid solution strengthening effect of Mn and high ductility in the as-cast condition, with additional hardness (strength) when the alloy contains the Mn carbide phase.

Details

ISSN :
15431916 and 10735615
Volume :
45
Database :
OpenAIRE
Journal :
Metallurgical and Materials Transactions B
Accession number :
edsair.doi...........f62739223fdad4f6b7e1b4f36f5dd104
Full Text :
https://doi.org/10.1007/s11663-014-0080-5