A Moessbauer evaluation of the 57Fe Debye temperatures in the Zr(AlxFe1-x)2 system

The Moessbauer recoiless absorption of 57Fe was utilized to monitor the iron cohesion properties in the Zr(AlxFe1-x)2 system for a wide range of compositions, 0 ≤ x ≤ 0.825. Moessbauer spectral area ratios were accurately measured for those samples at three temperatures sets, 423 K and 298 K, 433 K and 303 K, 612 K and 303 K. These ratios depend on the recoil free fractions, f(T), of the absorber at the corresponding temperatures. An experimental area ratio may provide a single parameter, i.e. the Debye temperature, θD, after assuming the Debye approximation. The results indicate a gradual decrease of the iron bonding strength from x = 0 to x = 0.2, demonstrated by a corresponding θD reduction from about 440 K to 310 K. The Debye temperature increases again to approximately 400 K for the Al-rich compounds. This behavior conforms with a previously proposed rule of reverse hydrogen absorption capacity in the above system. (orig.)