Influence of copper on the structural, mechanical, and biological characteristics of Mg–1Al–Cu alloy

Narges Safari, Mohammad Reza Toroghinejad, Mahshid Kharaziha

The aim of this study was to develop biodegradable and antibacterial Mg–Al–Cu alloys consisting of various amounts of Cu content (0, 0.25, 0.5 and 1 wt%) using spark plasma sintering (SPS) approach. Moreover, the role of Cu on the physical and biological properties of the alloys was investigated. The results indicated the formation of Al2Cu intermetallic phase during the SPS process significantly improved the mechanical properties of Mg based alloys. Specifically, the compressive strength and yield strength of pure Mg (167 ± 9 MPa and 69 ± 9 MPa, respectively) significantly enhanced to 232 ± 2 MPa and 94 ± 9 MPa, respectively, in Mg–1Al-0.25Cu alloy. Moreover, formation of tertiary alloy simultaneously improved the degradation rate, biocompatibility and antibacterial properties of pure Mg, depending on the Cu concentration. Noticeably, incorporation of 0.25 wt% Cu significantly diminished degradation rate from 0.039 cm/h in pure Mg to 0.00584 cm/h in Mg–1Al-0.25Cu alloy. Moreover, Mg–1Al-0.25Cu alloy noticeably promoted viability of MG63 cells compared to pure Mg, owing to the optimized ion release. The antibacterial activity results of samples against Escherichia coli and Staphylococcus aureus revealed that Mg–Al–Cu significantly prevented from the growth of bacteria, depending on the Cu content. In summary, Mg–Al-0.25Cu alloy with suitable mechanical characteristics, diminished degradation rate, good biocompatibility and antibacterial activities might be a promising biodegradable material for orthopedic implant.