液氮辅助冷却条件下激光熔凝AZ31B镁合金表面改性层（英文）

发布时间：2018-05-31 09:50

本文选题：镁合金 + 激光表面熔凝　；参考：《Transactions of Nonferrous Metals Society of China》2015年05期

【摘要】：激光表面熔凝技术是镁合金表面改性方法之一。为了进一步提高镁合金的表面性能,提出了液氮辅助冷却与激光熔凝相结合的方法,通过改变镁合金基体温度,加快改性层的凝固速度来改善镁合金的表面性能。结果表明,与室温氩气保护条件下相比,液氮辅助冷却条件下,镁合金表面形成一层较薄的改性层,晶粒显著细化,并在其上表层形成了大量"蠕虫状"的纳米晶,局部还出现少量的非晶组织,其显微硬度为HV 90~148,比在室温氩气保护条件下(硬度为HV 60~105)提高了约40%。在3.5%Na Cl溶液中进行电化学测试,结果表明,液氮辅助冷却条件下改性层的耐蚀性显著提高,其原因主要是由于快速凝固过程中晶粒细化、第二相β-Mg17Al12的再分配及局部非晶组织综合因素的结果。
[Abstract]:Laser surface melting is one of the surface modification methods for magnesium alloys. In order to further improve the surface properties of magnesium alloys, a method of combining liquid nitrogen assisted cooling with laser melting was proposed to improve the surface properties of magnesium alloys by changing the substrate temperature and accelerating the solidification rate of the modified layer. The results show that a thin modified layer is formed on the surface of magnesium alloy and a large number of "wormlike" nanocrystals are formed on the surface of magnesium alloy under the condition of argon protection at room temperature. A small amount of amorphous microstructure was also found in the region, the microhardness of which was HV90 and 148, which was about 40% higher than that under argon protection at room temperature (hardness was HV60 / 105). The electrochemical test in 3.5%Na Cl solution showed that the corrosion resistance of the modified layer was significantly improved under the condition of liquid nitrogen assisted cooling, which was mainly due to grain refinement during rapid solidification. The redistribution of the second phase 尾 -Mg17Al12 and the results of the comprehensive factors of the local amorphous structure.
【作者单位】：太原理工大学材料科学与工程学院;太原理工大学新材料界面科学与工程教育部重点实验室;
【基金】：Project(51305292)supported by the National Natural Science Foundation of China Project(2014-024)supported by Shanxi Scholarship Council of China
【分类号】：TG178

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