Effect of heat treatment an‎d number of hot ECAP passes on the microstructure an‎d biodegradability properties of Zn-1.5Mg alloy

10/21/2026 12:00:00 AM

In this study, the Zn-1.5Mg alloy was investigated to eva‎luate the effect of the number of passes in the hot Equal Channel Angular Pressing (ECAP) process an‎d subsequent annealing treatment on its microstructure an‎d corrosion behavior. The ECAP process was conducted at 150 °C, using die angles of Φ = 90° an‎d Ψ = 22°, along route Bc, for up to four passes. After ECAP, the samples were annealed at 50 °C an‎d 100 °C for 60 minutes.Microstructural analysis revealed that the grain size of the as-cast an‎d homogenized alloy decreased from about 30 µm to 3.85 µm after one ECAP pass an‎d further to 3.50 µm after four passes. Subsequent annealing reduced the grain size to 3.04 µm at 50 °C an‎d 2.50 µm at 100 °C, corresponding to nearly a 30-fold grain refinement compared to the initial state.Electrochemical corrosion tests showed that the corrosion potential increased from −1.026 V (as-cast) to −0.234 V after one ECAP pass, indicating improved corrosion resistance. The corrosion current density decreased from 18.39 µA/cm² to 0.50 µA/cm², while the polarization resistance increased from 2402 Ω·cm² to 3494 Ω·cm². Although higher ECAP passes slightly increased the corrosion rate, annealing at 100 °C significantly enhanced the corrosion resistance again.Overall, the ECAP process induced severe plastic deformation, resulting in remarkable grain refinement an‎d a more uniform distribution of intermetallic phases. Post-ECAP annealing, particularly at 100 °C, reduced internal stresses an‎d improved structural homogeneity, leading to the optimal combination of nanoscale microstructure an‎d corrosion resistance. Therefore, the condition of four ECAP passes followed by annealing at 100 °C was identified as the most effective for improving both the mechanical an‎d biodegradation properties of the Zn-1.5Mg alloy

ريز ساختار , آلياژ Zn-Mg , زيست تخريب پذيري , ECAP گرم , عمليات حرارتي

microstructure , Zn-Mg alloy , Biodegradability , Hot ECAP , Heat treatment

Samaneh Fallah

Dr. Hamidreza Jafarian