Glass forming ability and crystallization behaviors of the Ti-Cu-Ni-(Sn) alloys with large supercooled liquid region

The thermal stability and crystallization behavior of melt spun amorphous Ti-Cu-Ni-(Sn) alloys are investigated by thermal analysis and structural characterization with the intention to find alloy composition with wide supercooled liquid regime DeltaT(x), DeltaT(x) of amorphous Ti50CU50-xNix alloys increased with increasing Ni content up to 15 at% and then decreased with further increasing. Maximum DeltaT(x) of 46 K was obtained in Ti50Cu35Ni15 alloy. Partial replacement of Cu by Sn improved thermal stability of amorphous phase and DeltaT(x). Maximum DeltaT(x) of 73 K was obtained from melt spun amorphous Ti50Cu32Ni15Sn3 alloy. Amorphous Ti50Cu35Ni15 alloy crystallized by precipitation of supersaturated cubic Ti(Ni,Cu) phase followed by decomposition into a mixture of TiCu and TiNi at higher temperature. Amorphous Ti50Cu32Ni15Sn3 phase crystallized by co-precipitation of Ti(Ni,Cu) phase and Ti2Ni phases, followed by transformation into a mixture of TiNi, TiCu, Ti3Sn phases.