<報文>発光メスバウアー分光による TiNi のマルテンサイト変態の研究

概要

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Mossbauer spectroscopic study was performed on the ^<57>Co-doped Ti_<49.9>Ni_<50.1> and Ti_<48.3> Ni_<51.7> alloys in order to obtain additional informations on the martensitic transformation. The spectra consists of two singlet absorption lines which are due to the Fe(Co) impurities substituted at the Ti and Ni sites, respectively. The temperature variations of isomer shifts and effective halfwidths can be interpreted only by postulating two kinds of premartensitic phase. The one exists together with the martensitic phase in the temperature range between A_s and A_f, and the other between A_f and A_f+40K. Thermal scans of the resonant γ-ray transmission rate were measured at the Doppler velocities between ±1.9mm/sec and the zero-velocity, in order to observe the temperatuture variation of recoilless fraction. The anomalous decreases of recoilless fraction originated from lattice softening were found around two temperature regions which are M_s+85K∿M_s+135K and M_s+45∿M_s+55K. The results are discussed by bringing a comparison with the charge-density wave (CDW) model and the modulated lattice relaxation (MLR) model.TiNi alloymartensitic transformationMossbauer effectpremartensitic phaseisomer shiftquadrupole splittingcharge-density waveembryolattice softeningsoft phonon
東北大学の論文
1991-12-27