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为改善Mg-Al合金变质方法的不足,首先对常用的MgCO_3变质进行了热力学分析,并提出将CO_2气体直接通入AM60B合金熔体中,应能达到与MgCO_3变质相当甚至更优的晶粒细化效果。通过对比试验发现,MgCO_3可使AM60B合金的晶粒尺寸从未变质的213μm减小到113μm,硬度提高11.48%;用等量的CO_2气体处理,则使AM60B合金晶粒尺寸减小到了91μm,硬度提高了8.32%。通过SEM、EDS以及XRD分析表明,MgCO_3变质和CO_2气体变质具有相同的变质效果,这主要是熔体中的Al和C结合生成了Al4C3异质形核核心,进而细化AM60B合金的晶粒尺寸。
In order to improve the deficiency of Mg-Al alloy modification method, the thermodynamics analysis of commonly used MgCO_3 modification was proposed. It was proposed that the CO_2 gas should be directly introduced into the melt of AM60B alloy, and should be able to achieve the grain size reduction of MgCO_3 equivalent or even better Effect. Through comparative experiments, it was found that the grain size of AM60B alloy decreased from 213μm to 113μm without modification and the hardness increased by 11.48%. With the same amount of CO_2 gas treatment, the grain size of AM60B alloy was reduced to 91μm. The hardness Increased by 8.32%. The results of SEM, EDS and XRD show that the metamorphism of MgCO_3 metamorphism and CO_2 gas have the same metamorphism, which is mainly caused by the combination of Al and C in the melt to form heterogeneous nuclei of Al4C3 and refine the grain size of AM60B alloy .