Thermal stability of Ti₄₁Zr₄₁Si₁₈ metallic glass studied by small‐angle neutron scattering

Abstract

The thermal stability of amorphous Ti4,Zr4, Si,, alloys is studied by small-angle neutron scattering. In as-quenched samples inhomogeneities of 8.1 nm in radius are observed which disappeared during a low temperature (250 "C) annealing treatment. The annealing carried out a 500 "C for different times (10, 30, 60 min, and 24 h) leads to a considerable increase of the scattered intensity. Because of the interparticle correlation the dimensions of the particles must be determined by the least-squares fitting of the total scattering cross-section formula to the measured intensity pattern. The dimensions of the particles obtained in this way do not explain the non-monotonous time course of the scattered intensity. Therefore it is concluded that the scattering length density of the particles, that is their composition, has changed during the high temperature annealing treatment.La stabilite thermique des alliages amorphes Ti41Zr41Si18 a ete etudiee par diffusion aux petits angles. Dans I'echantillon trempe, des heterogtneites de 8.1 nm ont kte observees et disparaissent lors d'un traitement de revenu a basse temperature (250 "C). Le traitement thermique a 500 "C a etk effectue duree du temps differents (10, 20, 60 min et 24 h) en resultant une augmentation considerable de I'intensite diffusee. A cause de la correlation interparticulaire les dimensions des particules dans l'echantillon ont ete determintes par l'ajustement type moins quarrt de I'intensitk mesuree i la formule de la section eficace total de la diffusion. Ces dimensions obtenues n'expliques pas la tenue non-monotonique en temps de l'intensite diffusee. En consequence le densite de la longueur de diffusion, cet-a-dire la composition des particules changeait au cour du traitement a haut temperature.