Formation of amorphous Cu-Ag-Ce alloys by rapid solidification and their thermal and mechanical properties

New amorphous alloys in the Cu-Ag-Ce system have been found to form in a wide composition range of 5 to 55 at% Ag and 3 to 10%Ce by melt spinning. The crystallization temperature increases from 446 to 580 K with decreasing Ag content and increasing Ce content. Similarly, the tensile fracture strength and Vickers hardness increase to 755 MPa and 320, respectively, with increasing Ce content. The decrease in Ce content causes the structural change of the amorphous, fcc single phase and coexistent fcc Cu(Ag, Ce) and fcc Ag(Cu, Ce) phases. The dissolution of Ce into insoluble Cu-Ag alloys is very effective for the increase in the glass-forming ability as well as for the formation of the metastable fcc solution. The eutectic temperature also decreases from 1041 K for the binary Cu-Ag system to 1012 K for the ternary Cu-Ag-Ce system. Based on these results, the increase in the glass-forming ability by the dissolution of Ce may be attributed to the increase in the difficulty in the transition into a crystalline phase resulting from the increase in the random packing density for the supercooled liquid consisting of the three elements with significantly different atomic sizes.