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Title: Thermal conductivity of ruthenium aluminide (RuAl)

Abstract

Ruthenium aluminide (RuAl) is an intermetallic compound which exhibits strength at high temperatures together with attractive room temperature toughness. This combination of properties makes it a promising material for use at higher temperatures than currently possible with conventional titanium and nickel based alloys. Although high temperature applications will demand a knowledge and understanding of the thermal properties of RuAl, no such information is available in the scientific literature. In this paper, measurements of the thermal conductivity of RuAl are reported for the first time. Although the electrical properties of RuAl have previously been investigated, further electrical resistivity measurements have been made, using the same samples used to measure thermal conductivity. This allows a direct, meaningful comparison of electrical and thermal conductivity data, offering insights into the thermal transport mechanisms in RuAl. Microstructure is shown to have a significant influence on thermal and electrical properties.

Authors:
;  [1]
  1. Univ. of Cape Town, Rondebosch (South Africa). Dept. of Materials Engineering
Publication Date:
OSTI Identifier:
603884
Resource Type:
Journal Article
Resource Relation:
Journal Name: Scripta Materialia; Journal Volume: 38; Journal Issue: 3; Other Information: PBD: 6 Jan 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RUTHENIUM ALLOYS; ALUMINIUM ALLOYS; THERMAL CONDUCTIVITY; MICROSTRUCTURE; ELECTRICAL PROPERTIES; HEAT RESISTING ALLOYS

Citation Formats

Anderson, S.A., and Lang, C.I.. Thermal conductivity of ruthenium aluminide (RuAl). United States: N. p., 1998. Web. doi:10.1016/S1359-6462(97)00439-9.
Anderson, S.A., & Lang, C.I.. Thermal conductivity of ruthenium aluminide (RuAl). United States. doi:10.1016/S1359-6462(97)00439-9.
Anderson, S.A., and Lang, C.I.. Tue . "Thermal conductivity of ruthenium aluminide (RuAl)". United States. doi:10.1016/S1359-6462(97)00439-9.
@article{osti_603884,
title = {Thermal conductivity of ruthenium aluminide (RuAl)},
author = {Anderson, S.A. and Lang, C.I.},
abstractNote = {Ruthenium aluminide (RuAl) is an intermetallic compound which exhibits strength at high temperatures together with attractive room temperature toughness. This combination of properties makes it a promising material for use at higher temperatures than currently possible with conventional titanium and nickel based alloys. Although high temperature applications will demand a knowledge and understanding of the thermal properties of RuAl, no such information is available in the scientific literature. In this paper, measurements of the thermal conductivity of RuAl are reported for the first time. Although the electrical properties of RuAl have previously been investigated, further electrical resistivity measurements have been made, using the same samples used to measure thermal conductivity. This allows a direct, meaningful comparison of electrical and thermal conductivity data, offering insights into the thermal transport mechanisms in RuAl. Microstructure is shown to have a significant influence on thermal and electrical properties.},
doi = {10.1016/S1359-6462(97)00439-9},
journal = {Scripta Materialia},
number = 3,
volume = 38,
place = {United States},
year = {Tue Jan 06 00:00:00 EST 1998},
month = {Tue Jan 06 00:00:00 EST 1998}
}
  • Thermal conductivity values of Fe77Al23, Fe73Al27, and Fe76Al24 alloys were determined as a function of temperature, over a wide range of temperatures up to 1200 C. It was found that thermal conductivities of iron aluminide alloys in the region of Fe3Al increased linearly with temperature and that compositional differences had little effect. 6 refs.
  • The flow behavior and dislocation substructure present in ruthenium aluminide polycrystals due to deformation at room temperature and 77 K have been studied. Dislocations with three different types of Burgers vectors have been identified after 1--2% deformation in compression at 77 K and room temperature: {l_angle}100{r_angle}, {l_angle}110{r_angle} and {l_angle}111{r_angle}. The {l_angle}100{r_angle} and {l_angle}110{r_angle} dislocations are present with approximately equal densities, while the {l_angle}111{r_angle} are only occasionally observed. Trace analyses show that the majority of the dislocations are mixed in character and lie on {l_angle}110{r_angle} type planes. The implications of these observations with regard to the number of independent slip systemsmore » and the intrinsic deformability of this material are discussed.« less
  • Because of the need for new high temperature structural materials, a number of binary and multicomponent B2 aluminides have been investigated in recent years. Some alloys based on FeAl and Nb-Ti-Al are relatively ductile at low temperatures, but suffer from environmental embrittlement and/or relatively low melting temperatures. One apparent exception to the brittle behavior of the higher temperature B2 aluminides is ruthenium aluminide, RuAl, which has a melting point of approximately 2,060 C. Fleischer et al. have reported a high room temperature toughness and high compressive ductilities for a number of alloys based on RuAl, compared to a variety ofmore » other intermetallic compounds. The objective of the experiments reported here was to measure room temperature rate sensitivities for a number of the same RuAl-based alloys, to determine if the phenomenological flow parameters that relate to dislocation glide processes are also unusual, compared to other higher temperature B2 compounds.« less
  • The electrical properties of alloys of the ruthenium-aluminum system have not previously been the subject of a published work, although the mechanical properties and electronic structure have been investigated. The intermetallic compound ruthenium aluminide (RuAl) is reported to exhibit toughness and good ductility under compression at ambient temperatures, relative to other intermetallic materials, as well as strength and oxidation resistance at elevated temperatures. In the work described in the present paper, a series of alloys in the vicinity of the equiatomic composition, together with alloys close to the eutectic composition, have been investigated in order to determine the influence ofmore » composition and temperature on electrical resistivity and thermo-emf.« less
  • The unusual combination of high-temperature strength and room-temperature ductility makes compounds based on RuAl attractive for structural applications. Difficulties inherent in the manufacture of RuAl by melt processing can be circumvented by powder metallurgical (PM) techniques. The present work shows that reactive hot isostatic pressing (RHIPing) based on the self-propagating exothermic reaction of the constituent powders allows homogeneous, high-density material to be made. Controlled process parameters include green density, prior degassing, the powder size distribution, heating rate, pressure, and homogenizing schedule. The nature of the reaction products was found to be determined primarily by the applied pressure during combustion. Whilemore » concurrent pressure is required to ensure densification, pressurization leads to the formation of a host of nonequilibrium phases that necessitate extended homogenizing practices to drive the reaction to completion. The readily assimilable process parameters allow the production of structural components based on RuAl o be envisaged.« less