Probe–impurity interaction in dilute alloy ZrxHf1−x (x~0.98): Results from perturbed angular correlation measurements

•Zr metal with ~2 at% Hf is studied by TDPAC.•Two quadrupole interactions are observed.•Pure component with 12 NN Zr increases with temperature.•Ratio of impurity to pure fraction follows the Arrhenius law.•Formation entropy and binding energy of probe–impurity are measured.

Time-differential perturbed angular correlation measurements have been performed in Zr metal with ~2 at% Hf to understand the results of previous measurements. From present measurements at different temperatures two interaction frequencies have been found. One of these produces an asymmetry parameter η=0 as expected for a hcp crystal while the other one gives a non-zero value of η. The component with η=0 gives a value of quadrupole frequency ωQ=47.4(3) Mrad/s at 298 K while the second component produces values of ωQ=49.5(2) Mrad/s, η=0.22(1) at room temperature. The component with η=0 has been attributed to a configuration where all the 12 nearest neighbor (NN) to the probe has Zr atoms while the non-zero η component arises due to the presence of 1 NN Hf. The site fractions for these two components depend on temperature and it is found that with increase in temperature, the ratio f/(1−f) decreases following the Arrhenius behavior, f is the component fraction for the probe–impurity interaction. The entropy of formation and binding energy for the probe–impurity pair have been determined in the present report.