摘要
研究了SrCO_3对AZ31镁合金凝固组织的影响。结果表明:在AZ31中添加0.6%的SrCO_3,于760℃时保温10min细化效果最佳,α-Mg晶粒的尺寸由基体合金的570±15μm降至110±10μm,降幅约80.7%。通过能谱分析,结合能计算及自由能计算证实细化机理是SrCO_3反应后生成的部分Al_4C_3质点作为异质核心细化晶粒。多余的Al_4C_3质点钉扎晶界阻碍晶粒长大。Al元素随固/液界面前沿被快速推至晶界,生成沿晶界生长的β-Mg_(17)Al_(12)相,起到进一步固定晶界的作用。
The influence of SrCO_3 on the microstructure of AZ31 magnesium alloy has been investigated.The results show that AZ31 magnesium alloy has the best refining effect when the AZ31 magnesium alloy with addition of 0.6%SrCO_3 in 760℃,the average grain size of theα-Mg grain decreases from about 570±15μm of AZ31 base alloy to 110±10μm,the reduced extent is about 80.7%.Based on the analysis of EDS,Ebind and Gibbs free energy,the mechanism of grain refiner was generation of AI_4C_3 that can be used as crystallization center of the Mg when SrCO_3 added.Due to the generation of AI_4C_3 in AZ31 magnesium alloy,the grain boundary is pined and the grain growth is limited.The Al element was quickly pushed to the grain boundary along with the solid/quid intergace.and generated theβ-Mg_（17）AI_（12） phase along the grain boundary which has an effect of immobilizing the grain boundaries.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2010年第6期597-602,共6页
Chinese Journal of Materials Research
基金
国家重点基础研究发展计划2007CB613701和2007CB613702
国家自然科学基金50904018
51004032和50974037
中央高校基本科研业务费90409002和90209002资助项目~~
