碳酸盐矿石对AZ31镁合金晶粒细化与机理研究  

Research on Grain Refining Process and Mechanism of AZ31 Magnesium Alloys by Carbonate Ores

作　　者：刘轩 薛济来[1] 乐启炽[2] 张志强[2] LIU Xuan;XUE Jilai;LE Qichi;ZHANG Zhiqiang(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Lab of Materials Electromagnetic Processing,Ministry,Northeastern University,Shenyang 110819,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]东北大学材料电磁过程教育部重点实验室,辽宁沈阳110819

出　　处：《铸造技术》2018年第12期2717-2723,共7页Foundry Technology

基　　金：国家自然科学基金资助项目(51704020);中央高校基本科研业务费专项资金资助项目(FRF-TP-17-035A1;FRF-BD-17-010A)

摘　　要：针对商用AZ系镁合金缺乏可工业化应用的碳质细化剂,提出利用白云石、菱镁石和石灰石3种碳酸盐矿石作为经济有效的晶粒细化剂,研究工艺参数对矿石细化效果的影响规律,优化碳酸盐矿石细化工艺参数,并通过比较3种矿石细化效果,研究其细化机理。结果表明,碳酸盐矿石均对工业纯镁无显著细化效果,但添加石灰石后纯镁凝固组织心部出现细小等轴晶区,这与所含微量杂质Al_2O_3置换反应生成碳质细化所需的Al有关。碳酸盐矿石能显著细化AZ31凝固组织,其细化效果与矿石添加量和粒度有关。碳酸盐矿石细化AZ系镁合金的本质为矿石分解提供的C源,与Al和Mn形成Al-Mn/Al-C相可作为α-Mg的有效异质核心,且该相中Al-C层中Al含量较低。Carbon inoculation were considered to be the most effective grain refiner for Mg-Al alloys, and had been used for decades. The dolomite, magnesite and limestone three types of carbonate minerals were proposed as economic effective grain refining agent. The influence law of process parameters on the ore refining effect was studied, carbonate ore refining process parameters were optimized, and through the comparison of three kinds of ore refining effect, the refinement mechanism was studied. The results show that the carbonate minerals for the industrial pure magnesium are no significant refinement effect, but the center of the solidified structure of pure magnesium after adding limestone to constrict isometric zone, the Al2O3 displacement response and the content of trace impurities generated carbonaceous refinement needed for Al. Carbonate minerals can significantly refine AZ31 solidified structure, the refining effect is related to mineral content and granularity. Carbonate minerals refined AZ is the essence of the magnesium alloy C source for ore decomposition, with Al and Mn form Al-Mn/Al-C phase can be used as effective heterogeneous core of alpha Mg, Al-C layer and the phases of the Al content is low.

关 键 词：镁合金 碳质细化剂 碳酸盐矿石 凝固组织 晶粒细化 

分 类 号：TG292[金属学及工艺—铸造]