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It is known that the grain size plays a major role in the mechanical properties of magnesium. The aim of the present study is to evaluate its role in long‐term corrosion rate. Samples of pure magnesium with grain sizes in the range of 0.9–82 μm are produced through severe plastic deformation and annealing treatments. The mechanical properties are evaluated using tensile tests and the corrosion behavior is evaluated using immersion tests in Hank's solution. A maximum yield stress of ≈150 MPa is observed in the sample with 1.8 μm of grain size and an elongation larger than 25% is observed in the ultrafine‐grained sample. Ultrafine‐ and fine‐grained magnesium display uniform corrosion with a decreasing corrosion rate while coarse‐grained magnesium displays localized corrosion with an accelerated corrosion rate. A corrosion rate of ≈0.2 mm year−1is observed in the ultrafine‐ and fine‐grained magnesium. The corrosion product layer of the fine‐grained magnesium contains elements absorbed from the media. An analysis of the data in the literature suggests that grain refinement changes the corrosion type from localized to uniform corrosion. The exact relationship between grain size and the corrosion rate remains elusive.
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This content will become publicly available on November 22, 2025
Fabrication and Processing of Magnesium-Based Metal Matrix Nanocomposites for Bioabsorbable Implants
A novel magnesium (Mg)-based metal matrix nanocomposite (MMNC) was fabricated using ultrasonic melt treatment to promote the de-agglomeration of the bioactive glass–ceramic nanoparticles and the homogenization of the melt. The cast samples were then heat treated, machined, and hot rolled to reduce grain size and remove structural defects. Standard mechanical and electrochemical tests were conducted to determine the effect of fabrication and processing on the mechanical and corrosion properties of MMNCs. Compression tests, potentiodynamic polarization tests, electrochemical impedance spectroscopy, and static immersion testing were conducted to determine the characteristics of the MMNCs. The results showed that the combination of ultrasonic melt processing and thermomechanical processing caused the corrosion rate to increase from 8.7 mmpy after 10 days of immersion to 22.25 mmpy when compared with the ultrasonicated MMNCs but remained stable throughout the immersion time, showing no statistically significant change during the incubation periods. These samples also experienced increased yield stress (135.5 MPa) and decreased elongation at break (21.92%) due to the significant amount of grain refinement compared to the ultrasonicated MMNC (σY = 59.6 MPa, elongation = 40.44%). The MMNCs that underwent ultrasonic melt treatment also exhibited significant differences in the corrosion rate calculated from immersion tests.
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- Award ID(s):
- 2142610
- PAR ID:
- 10567899
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Metals
- Volume:
- 14
- Issue:
- 12
- ISSN:
- 2075-4701
- Page Range / eLocation ID:
- 1318
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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