Nanostructured bulk glassy Cu60Zr30Ti10 alloy with high strength and good ductility in cast state
(1. Institute for Materials Research,
Tohoku University, Sendai 980-8577, Japan;
2. National Enterprise Technology Center,
Wuhan Iron and Steel(Group)Co., Wuhan 430080, China)
Tohoku University, Sendai 980-8577, Japan;
2. National Enterprise Technology Center,
Wuhan Iron and Steel(Group)Co., Wuhan 430080, China)
Abstract: The bulk glassy Cu60Zr30Ti10 alloy with a diameter up to 4mm and a length of 70mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37K. The glass transition temperature (Tg) and the reduced glass transition temperature (Tg/Tl) of the cast bulk glassy Cu60Zr30Ti10 alloy are 713K 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 114GPa, 1785MPa, 2150MPa and 3.3% respectively in compressive deformation, and 112GPa, 1780MPa,2000MPa 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 Cu60Zr30Ti10 alloy consists of nanocrystals with a size of -4nm embedded in glassy matrix. The nanoparticle is identified as CuZr and has point space group symmetry of pm3-mand its lattice parameter is a=0.3262nm . The nanocrystalline phase grew up to 10nm upon annealing at 430℃ for 10min and caused the alloy brittle.
Key words: bulk glassy Cu60Zr30Ti10 alloy; casting; microstructure; nanocrystalline phase; mechanical property