Mechanical and corrosion properties of biodegradable Mg-1.5Mn-1Ca-xSr alloys

The mechanical properties and corrosion mechanism of both as-cast and solution-naturally age (T4) treated Mg-1.5Mn-1Ca-xSr alloys were investigated. The results showed that Sr is helpful to decrease grain size and increase the strength. The corrosion process of alloys was mainly determined by the quantity and distribution of second phases. Mg₁₇Sr₂, α-Mn and Ca-Sr phases acted as cathodes accelerated the corrosion of Mg₂Ca anodic phase and α-Mg matrix. However, continuous distributed Mg₁₇Sr₂ was beneficial to resist the happening of localized corrosion because of its barrier effect. T4 treatment could significantly improve the mechanical properties and corrosion resistance of Mg alloys because of the dissolution of Mg₂Ca phase and the dispersive distribution of Mg₁₇Sr₂ and α-Mn phases.