Solubility of hydrogen (1 atm, 298 K) in some copper/palladium alloys

The solubility of hydrogen (1 atm, 298 K) decreases linearily with copper content in f.c.c. substitutional Cu/Pd alloys to an atom fraction of Cu = 0.20 and thereafter the solubility decreases more abruptly. The fall in solubility at X_Cu > 0.20 is attributed to the inability of alloys with X_Cu > 0.20 to form a second non-stoichiometric hydride phase at 1 atm (298 K). Thermodynamic data are reported for the absorption of hydrogen into the two-phase regions (H-saturated alloy + non-stoichiometric hydride) of these alloys.