Medium-range order of liquid metal in the quenched state

摘要

The pre-peak of the structure factor S(Q) is found in Cu3Au liquid and its origin is analyzed by MD simulation in this paper. It is concluded from the calculation result of the Bhatia-Thornton (B-T) partial structure factor that the great concentration fluctuation in the liquid arising from strong chemical short order leads to the formation of pre-peak in the S(Q). In addition, the liquid system is quenched from two different temperatures in order to discuss the dynamics process of the glass formation in the paper. Although, the position of pre-peak and first peak are unchanged with quenching temperature, they become more pronounced in magnitude with the decrease of quenching temperature as a result of the increase of ordering degree of metallic glass. Further investigation on the structure indicates that the increases in intensity of pre-peak and first peak in the S(Q) during the cooling process results from the gradually enhanced icosahedral local order. Our present work provides an evolution picture of MRO in liquid metal undergoing different thermal histories. (C) 2004 Elsevier B.V. All rights reserved.