Nanostructured bulk glassy Cu60Zr30Ti10 alloy with high strength and good ductility in cast state

The bulk glassy Cu60 Zr30 Ti10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37 K. The glass transition temperature (Tg) and the reduced glass transition temperature (Tg/T1) of the cast bulk glassy Cu60Zr30Ti10 alloy are 713 K and 0.62. The cast bulk glassy alloy, which has high glassy forming ability, shows expected mechanical properties. The elastic modulus,yield strength, fracture strength and elongation including elastic elongation are 114 GPa, 1 785 MPa, 2 150 MPa and3. 3% respectively in compressive deformation, and 112 GPa, 1 780 MPa, 2 000 MPa and 1.9% respectively in tensile deformation. High resolution transmission electron microscope (HRTEM) and nano-beam electron diffraction(NBED) studies indicate that the cast metallic bulk glassy Cu60 Zr30 Til0 alloy consists of nanocrystals with a size of -4 nm embedded in glassy matrix.The nanoparticle is identified as CuZr and has point space group symmetry of pm3^-m and its lattice parameter is a=0.3262nm.The nanocrystalline phase grew up to 10 nm upon annealing at 430℃ for 10 min and caused the alloy brittle.