Structure,annealing characteristics and mechanical properties of Mg_(60)Cu_(30-y)Y_(10)Si_y bulk amorphous alloys

摘要

The effect of different Si contents on the glass forming ability (GFA) and the amorphous-to-crystalline transformation has been investigated for the Mg-Cu-Y-Si system.Four Mg_(60)Cu_(30-y)Y_(10)Si_y (y=1-5at%) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper mould.Crystallization was induced by heat treatment of the allys and the samples were then characterized concerning their microstructure and thermal stability by X-ray diffraction (XRD),optical (OM) and scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) at a constant heating rate.Partial substitution of Cu by Si leads to a transition of the as-cast structure at a constant cooling rate from amorphous to crystalline with increasing Si content.Furthermore,the glass transition temperature (T_g) of the Mg-Cu-Y-Si alloy is lower compared to the Mg-Cu-Y system.The mechanical properties of the bulk Mg-Cu-Y-Si alloys have been investigated and found to vary with the Si content.