激光表面强化对镁合金在模拟体液中腐蚀行为的影响

发布时间：2018-06-16 15:39

本文选题：镁合金 + SBF　；参考：《表面技术》2017年08期

【摘要】：目的通过对镁合金表面进行激光强化处理,改善医用AZ91D镁合金在模拟体液中的耐腐蚀性能。方法采用不同脉宽的Nd:YAG脉冲激光对医用AZ91D镁合金表面进行处理,激光能量密度分别为28、23、18 J/mm~2,对激光处理后镁合金强化层的组成、显微结构、厚度、元素分布以及耐腐蚀性能等进行测试和分析。结果 AZ91D经过激光强化处理后形成致密的强化层,强化层中相的组成与基材相的组成相同,均由α-Mg和β-Mg_(17)Al_(12)组成,强化层的厚度达到300μm。Mg和Mg_(17)Al_(12)的X射线衍射峰均向低角度偏移(约0.2°),且镁合金表面晶粒均得到细化,β相的大小从平均55.705μm减小到平均6.447μm。EDS分析表明,经过激光处理后,Mg的质量分数由82.88%减少为70.13%,Al的质量分数由16.28%增加为28.08%,且Al的分布更均匀。激光处理后,镁合金在模拟体液中的电化学测试结果表明,镁合金的腐蚀电位从原来的-1274mV增加到-1215 mV,腐蚀电流密度从8.920×10~(-5) A/cm~2减小为8.826×10~(-6) A/cm~2,同时,阻抗也从原来的1000Ω增加到60 000Ω,可知激光强化镁合金的耐腐蚀性能较原始镁合金的耐腐蚀性能均有一定程度的改善。结论医用AZ91D镁合金在不同脉宽的Nd:YAG脉冲激光处理后,表面晶粒得到了细化,强化层中富集Al,在模拟体液中的耐腐蚀性能得到改善。
[Abstract]:Objective to improve the corrosion resistance of medical AZ91D magnesium alloy in simulated body fluid by laser hardening. Methods the surface of medical AZ91D magnesium alloy was treated with ND: YAG pulsed laser with different pulse widths. The laser energy density was 28 ~ 2318 J / mm ~ (-2). Element distribution and corrosion resistance were tested and analyzed. Results after laser hardening, AZ91D formed a dense strengthening layer. The phase composition of AZ91D was the same as that of substrate phase, which consisted of 伪 -Mg and 尾 -Mg and 尾 -Mg17AlC12). The X ray diffraction peak of the strengthened layer with thickness of 300 渭 m mg and Mg1 17 Altix 12 shifts to a low angle (about 0. 2 掳), and the grains on the surface of magnesium alloy are refined, and the 尾 phase size decreases from an average of 55.705 渭 m to an average of 6.447 渭 m by EDS analysis. After laser treatment, the mass fraction of mg decreased from 82.88% to 70.13%, and the mass fraction of Al increased from 16.28% to 28.08, and the distribution of Al was more uniform. After laser treatment, the electrochemical measurements of magnesium alloy in simulated body fluid showed that the corrosion potential of magnesium alloy increased from -1274 MV to -1215 MV, and the corrosion current density decreased from 8.920 脳 10 ~ (-5) A/cm~2 to 8.826 脳 10 ~ (-6) A / cm ~ (-2), and the corrosion current density decreased to 8.826 脳 10 ~ (-6) A / cm ~ (-2). The impedance is also increased from 1000 惟 to 60 000 惟, which shows that the corrosion resistance of laser-strengthened magnesium alloy is better than that of original magnesium alloy to some extent. Conclusion the surface grain of medical AZ91D magnesium alloy treated with ND: YAG pulse laser with different pulse widths was refined, and the corrosion resistance in simulated body fluid was improved by enrichment of Al in the strengthened layer.
【作者单位】：兰州大学;中国科学院兰州物理化学研究所;
【基金】：国家自然科学基金青年科学基金项目(51505464)~~
【分类号】：TG146.22;TG665

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