New bulk glassy Ni-based alloys with high strength of 3000 MPa

Abstract

New Ni-based bulk glassy alloys with high strength and good ductility were synthesized for the first time in Ni-Nb-Ti-Zr base system by the mold-clamp or copper mold casting method. The bulk glassy Ni53Nb20Ti10Zr8Co6Cu3 alloy has a rod shape with diameters up to 3 mm or a sheet shape with thickness up to 1 mm. The glass transition temperature (Tg) and the supercooled liquid region defined by the difference between Tg and crystallization temperature (Tx), ΔTx (= Tx - Tg) are 846 and 51 K, respectively, and no distinct change in Tg, Tx and ΔTx with sample diameter is seen. The Ni-based alloy is located in the vicinity of eutectic composition and has a high reduced glass transition temperature (Tg/Tm) of 0.67. The Ni-based bulk glassy alloy also exhibits good mechanical properties, i.e.,tensile fracture strength of 2700 MPa, tensile fracture elongation of 2.1%, compressive fracture strength of 3010 MPa and compressive fracture elongation of 2.4%. It is noticed that the tensile fracture strength is the highest among all bulk glassy alloys developed up to date. The success of synthesizing the new Ni-based bulk glassy alloy with good mechanical properties is promising for future uses as a new type of high strength material.