A detailed microstructural and corrosion analysis of an additively manufactured magnesium alloy produced by selective laser melting
A detailed microstructural and corrosion analysis of an additively manufactured magnesium alloy produced by selective laser melting
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通过选择性激光熔化生产的增材制造镁合金的详细微观结构和腐蚀分析
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发表时间：
2020
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通讯作者：
N. Birbilis
中科院分区：
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作者：
M. Esmaily;Z. Zeng;N. Mortazavi;A. Gullino;S. Choudhary;T. Derra;F. Benn;F. Delia;M. Muether;Sebastian Thomas;A. Huang;A. Allanore;A. Kopp;N. Birbilis
镁合金在轻量化和生物医学领域具有广阔的应用前景。虽然最近人们对使用增材制造（AM）生产镁合金（包括AZ、ZK和WE系列）产生了兴趣，但AM镁合金的工艺-结构-腐蚀性能关系尚未被理解。本文采用选区激光熔化（SLM）技术制备了WE 43镁合金。该合金进行了SLM，热等静压（HIP），以及一个额外的固溶热处理后进行了研究。试样进行了仔细的特点，同时评估和对比相对于传统的铸造合金对应。表征包括采用分析型透射电子显微镜、X射线绘图和电子背散射衍射的详细微观结构分析，其揭示SLM制备的试样具有独特的微观结构，所述微观结构包括沿构建方向以强[0001]织构沿着生长的细晶粒。SLM制备的试样还显示出低比例的工艺诱导和冶金缺陷，在优化SLM参数和HIP处理后达到< 0.1%。SLM制备的WE 43被发现是阴极更积极的相对于铸造WE 43，因为锆，钇和富氧颗粒的精细分布，以及在源自SLM的高冷却速率的固溶体基质的化学组成的改变。结果表明，氧化物颗粒主要来源于粉末，因此可以推测，一旦进一步了解和控制粉末特性的影响，SLM制备的镁合金的腐蚀性可以得到很大改善。
Magnesium (Mg) alloys have promising potentials for lightweight and biomedical applications. Although there has been a recent interest in producing Mg alloys (including AZ, ZK and WE series) using additive manufacturing (AM), the process-structure-corrosion properties relationships in AM Mg alloys are yet to be understood. Herein, the production of Mg alloy WE43 was achieved by selective laser melting (SLM). The alloy was investigated after SLM, hot isostatic pressing (HIP) as well as an additional solutionising heat treatment. Specimens were carefully characterised, whilst assessed and contrast relative to the conventionally cast alloy counterpart. Characterisation included detailed microstructural analysis employing analytical transmission electron microscopy, X-ray mapping, and electron backscatter diffraction, which revealed the SLM prepared specimens possess a unique microstructure comprising fine grains growing with a strong [0001] texture along the building direction. The SLM prepared specimens also revealed a low fraction of process-induced and metallurgical defects, reaching < 0.1% after optimising the SLM parameters and HIP treatment. The SLM prepared WE43 was found to be cathodically more active relative to the cast WE43 because of a fine distribution of zirconium-, yttrium- and oxygen-rich particles as well as the alterations in the chemical composition of the solid-solution matrix originating from the high cooling rates of SLM. It was revealed that the oxide particles were mainly sourced by powder and thus it is hypothesised that the corrosion of SLM prepared Mg alloys could be greatly improved once the influence of powder characteristics is further understood and controlled.