title: Thermodynamic anomaly of the sub-T(g) relaxation in hyperquenched metallic glasses.
abstract: Recently, we observed an unusual non-monotonic glass relaxation phenomenon, i.e., the three-step sub-T(g) relaxation in hyperquenched CuZrAl glass ribbons [L. N. Hu and Y. Z. Yue, Appl. Phys. Lett. 98, 081904 (2011)]. In the present work, we reveal the origin of this abnormal behavior by studying the cooling rate dependence of the sub-T(g) enthalpy relaxation in two metallic glasses. For the Cu46Zr46Al8 glass ribbons the sub-T(g) enthalpy relaxation pattern exhibits a three-step trend with the annealing temperature only when the ribbons are fabricated below a critical cooling rate. For the La55Al25Ni20 glass ribbons the activation energy for the onset of the sub-T(g) enthalpy relaxation also varies non-monotonically with the cooling rate of fabrication. These abnormal relaxation phenomena are explained in terms of the competition between the low and the high temperature clusters during the fragile-to-strong transition. By comparisons of chemical heterogeneity between Cu46Zr46Al8 and La55Al25Ni20, we predict that the abnormal relaxation behavior could be a general feature for the HQ metallic glasses.
authors: Key Laboratory of Liquid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China. hulina0850@mail.sdu.edu.cn
authors: Lina
authors: L
authors: Hu
authors: Chao
authors: C
authors: Zhou
authors: Chunzhi
authors: C
authors: Zhang
authors: Yuanzheng
authors: Y
authors: Yue