Tensile properties of tungsten-3.6% rhenium-0.4% hafnium carbide above 0.5 T m

Abstract

In recent years, there has been a renewal of interest in the development of tungsten-base alloys and fibers as future aerospace propulsion and space power systems place over increasing demands on materials with high-temperature capability. For example, tungsten-base alloys are expected to be used as emitter materials in a future space power system and tungsten fiber-reinforced composites are being developed for future aerospace systems. Among various alloying elements for tungsten, rhenium has been found to be one of the most effective alloying elements because the addition of rhenium to tungsten increases not only high-temperature strength but low-temperature ductility. It has been reported that the optimum concentration of rhenium in tungsten is about 4 at.% or greater than 20 at.% to provide optimum ductilizing effect. In order to improve high-temperature strength, second-phase strengthening has also been utilized in the development of tungsten-base alloys. Among various potential second-phase particles, hafnium carbide (HfC) was found to be one of the most effective particles to improve high-temperature strength of tungsten because of its high melting temperature and thermodynamic stability. The main objective of the present paper is to report the tensile properties of a W-3.6 at.% Re-0.4 mol % HfC alloy for a widemore » temperature range above 0.5 T/sub m/ (melting temperature in Kelvin) and examine the strengthening effect of HfC.« less