Impact of microalloying element Ga on the glass-forming ability (GFA), mechanical properties and corrosion behavior of Mg–Zn–Ca bulk metallic glass

• Published in: Materials chemistry and physics 2020-11, Vol.255, p.123555, Article 123555
• Main Authors: Zai, Wei, Man, H.C., Su, Yingchao, Li, Guangyu, Lian, Jianshe
• Format: Article
• Language: English
• Subjects: Alloys; Amorphous materials; Backscattering; Binary alloys; Binary systems; Biodegradability; Biodegradable material; Bulk metallic glass; Calcium; Corrosion behavior; Corrosion effects; Corrosion mechanisms; Corrosion resistance; Electrochemical measurements; Fracture strength; Gallium; Glass formation; Glass substrates; Immersion tests (corrosion); Magnesium; Magnesium alloy; Materials selection; Mechanical properties; Metallic glasses; Microalloying; Phase diagrams; Zinc
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2020.123555

By virtue of its high corrosion resistance and desirable mechanical properties, Mg-based bulk metallic glass (BMG) is a promising candidate material for the biodegradable implants. To investigate the impact of microalloying element Ga on the glass-forming ability (GFA) and its effect on the mechanical properties and corrosion behaviors of Mg–Zn–Ca BMG, a series alloys of (Mg66Zn30Ca4)100-xGax (x = 0, 0.25, 0.5, 0.75, 1.0 and 1.25) were synthesized and investigated in this study. According to the XRD results and SEM (backscattered electron) images, the critical diameter (Dc) of Mg66Zn30Ca4 BMG is about 3.5 mm, and 1.0 at.% Ga addition improves the Dc to about 5 mm. Meanwhile, the 1.0 at.% Ga addition improves the fracture strength of Mg–Zn–Ca BMG from 651 MPa to 752 MPa. The corrosion behavior and mechanism of different metallic glass samples were investigated. According to the results of electrochemical tests and immersion test, the addition of Ga can help to form the passive film on the metallic glass substrate and improve its corrosion resistance. Besides, the relationship between the alloy composition and glass-forming ability (GFA) was postulated and interpreted by the theory of binary alloy phase diagrams. •Mg–Zn–Ca bulk metallic glasses with different content of Ga are prepared successfully.•Corrosion behavior and mechanical properties of different Mg–Zn–Ca-Ga bulk metallic glasses are investigated.•The relationship between glass-forming ability (GFA) and alloy phase diagrams is interpreted.