Centimeter-sized Ti-based bulk metallic glass with high specific strength

Based on the quaternary Ti41Zr25Be29Al5 glassy alloy with a critical diameter of 7 mm reported not long ago, an obvious enhancement of glass-forming ability (GFA) has been realized in this alloy by the addition of Cu element. A series of (Ti41Zr25Be29Al5)100−xCux (x=0, 2, 5, 7, 9, 11 at%) glassy alloys have been developed and some of them can be cast into one-centimeter diameter fully glassy rods by copper mold suction casting. It has been found that Cu addition could stabilize the liquid phase and suppress the crystallization, resulting in improvement of the GFA of the alloy. The addition of Cu also increases the compressive strength of the alloy and the (Ti41Zr25Be29Al5)91Cu9 glassy alloy possesses a specific strength (defined as yield strength/density) of 4.13×105 Nm/kg, which is much higher than most other reported centimeter-sized bulk metallic glasses. The present result suggests that the newly developed (Ti41Zr25Be29Al5)91Cu9 glassy alloy is a good candidate for structural applications because of its good glass-forming ability and mechanical properties.