High-Temperature Tensile Properties of a Molybdenum-5%Rhenium-0.5%Hafnium Carbide Alloy

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Tensile properties of a molybdenum‐5 at % rhenium‐0.5 at % hafnium carbide alloy were evaluated with a strain rate of 10−3/sec over a temperature region of 1200 to 2400 K in vacuum. The yield strength, tensile strength, solution induced and dispersion induced strength increments, strain‐hardening exponent, and tensile elongation of this alloy were determined. The effects of rhenium, hafnium carbide particles, and temperature on the strength properties were examined. The tensile properties of this alloy were compared with those of Mo‐0.5 at % hafnium carbide and pure molybdenum. It was found that the addition of rhenium and hafnium carbide resulted in a significant increase on the strength of molybdenum at high temperatures. Solution strengthening by rhenium was effective up to approximately 1800 K. The dispersion strengthening by dispersed hafnium carbide particles was significant in the entire temperature range employed. The high strength of molybdenum‐5 at% rhenium‐0.5 at % hafnium carbide was attributed mainly to the superior thermostability of hafnium carbide particles at high temperatures. The post‐test specimens were characterized with a scanning electron microscope and a transmission electron microscope. The strengthening mechanisms involved in molybdenum‐5 at % rhenium‐0.5 at % hafnium carbide included the long and short ranges interactions between the hafnium carbide dispersoids and the dislocations. The dominant deformation mechanism of this alloy was dislocation sliding up to 1800 K and was grain boundary sliding at higher temperatures.Tensile properties of a molybdenum‐5 at % rhenium‐0.5 at % hafnium carbide alloy were evaluated with a strain rate of 10−3/sec over a temperature region of 1200 to 2400 K in vacuum. The yield strength, tensile strength, solution induced and dispersion induced strength increments, strain‐hardening exponent, and tensile elongation of this alloy were determined. The effects of rhenium, hafnium carbide particles, and temperature on the strength properties were examined. The tensile properties of this alloy were compared with those of Mo‐0.5 at % hafnium carbide and pure molybdenum. It was found that the addition of rhenium and hafnium carbide resulted in a significant increase on the strength of molybdenum at high temperatures. Solution strengthening by rhenium was effective up to approximately 1800 K. The dispersion strengthening by dispersed hafnium carbide particles was significant in the entire temperature range employed. The high strength of molybdenum‐5 at% rhenium‐0.5 at % hafnium carbide was attribute...