Calculated phase diagrams and the corrosion of die-cast Mg–Al alloys

By Ming Liu, P. Uggowitzer, A. V. Nagasekhar, Patrik Schmutz, M. Easton, G. Song, A. Atrens. 2009

348 citations recorded by the source corpus.

Abstract The corrosion of commercial die-cast Mg–Al alloys was elucidated by a study, of the corrosion in 3% NaCl, of (i) high-pressure die-cast (HPDC) model Mg–Al alloys, (ii) low-purity Mg, (iii) high-purity (HP) Mg and (iv) HP Mg heat treated at 550 °C. HPDC is the most important route for the production of Mg components. The corrosion of the model alloys was dominated by the Fe impurity element. The present research identified the appearance of the Fe-rich particles in the microstructure. In high magnification (∼1000× to 5000×) secondary electron images, they appear as small white features, typically less than 1 μm in diameter. In order to understand the impurity tolerance limits, (i) the appropriate corrosion literature was summarised and reviewed and (ii) Mg phase diagrams were calculated using the Pandat software package. Calculated phase diagrams can explain (i) the tolerance levels for Fe and Cu and (ii) the production of high-purity castings by means of control of melt conditions; this has high significance for the production of quality castings from recycled Mg. A full analysis requires that the Mg database be extended to include Ni, Co and some RE. The Fe tolerance limit is ∼5–10 ppm for cast HP Mg heat treated at 550 °C. Analysis of the Mg corrosion literature indicates that several studies have been dominated by the Fe impurity content and have not dealt with the stated aims; it means that the full chemical composition should be reported in all studies of the corrosion of Mg alloys.

Subfields: Biomaterials, Mechanical Engineering, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/076cb6e00dfede707e2b05e7800bb7662029c04e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomaterials

1. A. Atrens
2. G. Song
3. Nick Birbilis
4. Ming Liu
5. N. Z. Abidin
6. S. Feliu
7. P. Uggowitzer
8. Patrik Schmutz

In Mechanical Engineering

1. A. Atrens
2. G. Song
3. Nick Birbilis
4. Ming Liu
5. N. Z. Abidin
6. P. Uggowitzer
7. Patrik Schmutz
8. Darren J. Martin

In Mechanics of Materials

1. A. Atrens
2. Ming Liu
3. G. Song
4. Nick Birbilis
5. N. Z. Abidin
6. P. Uggowitzer
7. Darren J. Martin
8. S. Virtanen

Citations in the corpus

• Effect of grain size and twins on corrosion behaviour of AZ31B magnesium alloy (2010, background): “Increasing Al concentration in Mg–Al alloys has a beneficial effect on the corrosion behaviour in chloride media [10], however, AZ31 alloy still presents high corrosion rates [9].”
• The influence of yttrium (Y) on the corrosion of Mg–Y binary alloys (2010, background): “LP Mg showed, in contrast, a low corrosion resistance during the whole immersion period attributed to the acceleration caused by the presence of the Fe-rich second phase [40].”
• Fundamentals and advances in magnesium alloy corrosion (2017, background): “1 mm/year (5 10 2 mg/cm(2)/day) to 15 mm/year (7 mg/cm(2)/day) for Mg alloys [103]) and corrosion mechanisms not observed in real service conditions, where other parameters need to be considered (i.”