Formation and properties of centimeter-size Zr–Ti–Cu–Al–Y bulk metallic glasses as potential biomaterials

A series of Ni-free (Zr0.5Ti0.02Cu0.38Al0.1)100−xYx (x = 0, 1, 2, 3 and 5 at.%) bulk metallic glasses (BMGs) with outstanding glass-forming ability (GFA) were synthesized by copper mold casting and the effects of yttrium addition on glass-formation, thermal stability, mechanical properties and in vitro biocompatibility of the BMGs were investigated. It was found that the addition of 1–3 at.% Y greatly enhanced the GFA and thermal stability of the Zr50Ti2Cu38Al10 alloy. The critical diameter (dc) increased from 5 mm for the Y-free alloy to 20 mm by 2 at.% Y addition. The supercooled liquid region (ΔTx) of the Zr-based alloys was also enlarged to 60–71 K by the 1–3 at.% Y doping from 59 K for the base alloy. The compressive strength and plastic strain decreased gradually with the increase in Y content, while the Zr-based BMGs containing 0–3 at.% Y still exhibited high yield strength of about 1750–1800 MPa and compressive plasticity. The Zr-based BMGs also exhibited Young's moduli of 82–89 GPa, which are lower than that of Ti–6Al–4V alloy. Cell proliferation and cytotoxicity of mouse MC3T3-E1 pre-osteoblast on the Zr-based BMGs demonstrated good biocompatibility comparable to Ti–6Al–4V alloy. The combination of outstanding GFA and good mechanical properties and in vitro biocompatibility makes these Ni-free Zr-based BMGs promising as biomedical materials. •Ni-free Zr–Ti–Cu–Al–Y BMGs with critical diameters up to 20 mm are synthesized.•The Zr–Ti–Cu–Al–Y BMGs possess low Young's moduli and high compressive strength.•The Zr–Ti–Cu–Al–Y BMGs exhibit good biocompatibility comparable to that of Ti–6Al–4V.•The Zr–Ti–Cu–Al–Y BMGs demonstrate the potential for use in biomedical applications.