Mg-rich Mg–Ni–Gd ternary bulk metallic glasses with high compressive specific strength and ductility

Abstract

In the present study, we show by tailoring the combinations of the bonding energy among the elements in the liquid state, glass forming ability and compressive mechanical properties of the metallic glasses (MGs) can be improved. The mixing enthalpy values for binary atom pairs in the ternary Mg–Ni–Gd alloys (Mg–Ni: −12 kJ/mol, Mg–Gd: −27 kJ/mol, Ni–Gd: −161 kJ/mol) covers a wide range, although they are all negative. Mg-rich Mg–Ni–Gd (Mg > 70 at.%) alloys can be readily solidified into an amorphous state in a wide composition range up to 4 mm in diameter using the injection casting method; they exhibit the highest level of glass transition temperature Tg among those reported in Mg-based MGs so far. In particular, Mg-rich Mg–Ni–Gd bulk metallic glasses with 10–15 at.% Ni and 10–15 at.% Gd exhibit high strength over 900 MPa and large plastic strain up to ∼2% during compressive loading.