THERMAL EXPANSIVITIES, THERMAL CONDUCTIVITIES, AND DENSITIES OF VANADIUM, TITANIUM, CHROMIUM AND SOME VANADIUM-BASE ALLOYS - (A COMPARISON WITH AUSTENITIC STAINLESS STEEL)

Computer-fitted polynomial expressions are presented that define the linear thermal-expansion behavior of vanadium, titanium, chromium, certain VTi and VTiCr alloys, and AISI Types 304 and 316 stainless steels between 0 ° and 1000 °C. The mean expansion coefficients for the vanadium-base alloys differ only slightly from those for unalloyed vanadium (plus or minus 6%), and are 65% to 80% lower than the mean expansion coefficients for the austenitic stainless steels. Densities of the vanadium-base alloys and the austenitic stainless steels were determined at 25 °C by liquid displacement. The VTi alloys show a non-linear decrease in density with increasing titanium for titanium contents greater than 30 wt.%. The VTiCr alloys also exhibit a non-linear change in density for compositions containing greater than 15 wt.% titanium, and greater than 5 wt.% chromium. A comparison of the mechanical and thermal properties of two vanadium-base alloys and two austenitic stainless steels was made to determine their relative usefulness as reactor fuel jackets for service between 500 ° and 700 °C. This comparison shows that vanadium alloy fuel jackets would be subjected to only one-third the thermal stresses generated in austenitic stainless steel jackets during reactor excursions between 500 ° and 700 °C under conditions where the fuel is not in intimate contact with the jacket. This difference in thermal stresses in the two jacket materials is the result of the 37% higher tensile strength, 40% higher thermal conductivity, and 70% lower thermal expansivity exhibited by the vanadium alloys as compared with austenitic stainless steel. © 1969.