Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Materials Science and Engineering


The dissolution of hydrogen gas has been studied by means of^hydrogen pressure-composition isotherms in strontium, thorium-^nitrogen and vanadium alloys containing either niobium, chromium^or titanium. Direct hydrogen equilibrium vapor pressure^measurements were performed in the strontium-hydrogen and^thorium-nitrogen-hydrogen systems in the ranges 973 to 1173 K^and 623 to 1123 K, respectively. An indirect method, an isopiestic^solubility technique, was employed to measure the hydrogen^equilibrium pressures for the vanadium alloys in the range 223 to^473 K. In all the alloys studied, the reaction of hydrogen with the^metal phase was exothermic and hydrogen followed Sieverts' law^over a considerable range of hydrogen concentration. The enthalpy^of solution of hydrogen in the strontium metal and the enthalpy of^formation of ThNH(,x) were determined to have the values of -14.3 (+OR-)^1.2 kcal/mol H and -16.3 (+OR-) 1.5 kcal/mol H(,2), respectively. The values^of the enthalpies of solution of hydrogen for the vanadium alloys^ranged from -8.0 to -10.5 (+OR-) 0.3 kcal/mol H. Additions of titanium^to vanadium dramatically enhanced the isopiestic solubility of^hydrogen, chromium significantly reduced the solubility and niobiummoderately increased the solubility. Sieverts' law behavior forhydrogen in the vanadium alloys showed that substitutional atoms;did not act as deep traps for hydrogen;*DOE Report IS-T-998. This work was performed under ContractW-7405-Eng-82 with the U.S. Department of Energy.



Digital Repository @ Iowa State University,

Copyright Owner

Stephen Otto Nelson



Proquest ID


File Format


File Size

78 pages

Included in

Metallurgy Commons