| GUO Chang-gang,XU Yi-meng,WANG Ling-qian,CAO Bao-cheng.Effect of Laser Surface Strengthening on Corrosion Behavior of Magnesium Alloy in Simulated Body Fluid[J],46(8):188-194 |
| Effect of Laser Surface Strengthening on Corrosion Behavior of Magnesium Alloy in Simulated Body Fluid |
| Received:February 13, 2017 Revised:August 20, 2017 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2017.08.031 |
| KeyWord:magnesium alloy SBF laser strengthening pulse width corrosion resistance surface treatment |
| Author | Institution |
| GUO Chang-gang |
Lanzhou University, Lanzhou , China |
| XU Yi-meng |
Lanzhou University, Lanzhou , China |
| WANG Ling-qian |
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| CAO Bao-cheng |
Lanzhou University, Lanzhou , China |
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| Abstract: |
| The work aims to improve corrosion resistance of AZ91D magnesium alloy in simulated body fluid by means of laser melting on the surface of magnesium alloy. Being treated with Nd:YAG pulse laser of different pulse width, laser energy density of medical AZ91D magnesium alloy was 28, 23, 18 J/mm2, respectively. Composition, microstructure, thickness, element distribution and corrosion resistance of the magnesium alloy strengthened layer were tested and analyzed. A dense melt layer was present on LSM-treated magnesium alloy AZ91D. Phase composition of the strengthened layer was identical to that of the substrate, both were composed of α-Mg and β-Mg17Al12. Thickness of the strengthened layer was over 300 microns. X-ray diffraction peaks of Mg and Mg17Al12 slightly shifted toward lower angles (about 0.2). Grains on the surface of the magnesium alloy were refined, size of β phase was reduced from an average of 55.705 μm to 6.447 μm. EDS analysis showed that, after laser treatment, Mg mass fraction was reduced from 82.88% to 70.13% while Al mass fraction increased from 16.28% to 28.08% and Al was distributed more uniformly. Electrochemical Al tests results in simulated body fluid after laser treatment indicated that corrosion potential of magnesium alloy increased from 1274 mV to 1215 mV, corrosion current increased from 8.920×105 A/cm2 to 8.826×106 A/cm2 and impedance also increased from 1000 Ω to 60 000 Ω, corrosion resistance of the laser strengthened magnesium alloy was better than that of the original magnesium alloy to certain degree. Surface grains are refined, Al is enriched on the strengthened layer and corrosion resistance of the medical AZ91D magnesium alloy was improved in simulated body fluid after Nd:YAG pulse laser treatment with different pulse width. |
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