镁对N06625合金铸态组织的影响  

Effect of magnesium on as-cast microstructure of N06625 alloy

作　　者：张海宝 刘福斌 姜周华 李花兵 耿鑫 ZHANG Haibao;LIU Fubin;JIANG Zhouhua;LI Huabing;GENG Xin(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819

出　　处：《中国冶金》2023年第7期51-58,共8页China Metallurgy

基　　金：山西省关键核心技术和共性技术研发攻关专项资助项目(20201102017);中央高校基本科研业务费资助项目(N2125030)。

摘　　要：N06625合金中含有大量强化元素,在凝固过程中会发生溶质再分配和组分过冷现象,从而对合金的微观组织结构产生重大影响。利用Thermo-Calc热力学软件计算分析了非平衡凝固过程中Mg含量对N06625合金相转变规律和残余液相中主要元素含量变化的影响,并通过光学显微镜(OM)和场发射扫描电镜(FESEM)研究了不同质量分数Mg(0、0.0052%、0.0081%和0.0250%)对N06625合金铸态组织产生的影响。结果表明,随着Mg含量升高,固液相温度区间增加,各相析出温度发生改变,但不改变析出相种类,且随着Mg含量增加,残余液相中Ni和Mg元素含量增加,Cr、Mo、Nb和C元素含量降低。未加Mg时,二次枝晶间距较大,析出相以条状和块状在枝晶间区域析出,其平均面积分数和尺寸较大;当合金中Mg质量分数从0增加到0.0052%、0.0081%时,二次枝晶间距发生细化,析出相的平均面积分数降低并产生细化球化作用,分布更加弥散,Ti、Cr、Mo和Nb元素偏析程度减弱;当Mg质量分数增加至0.0250%时,二次枝晶间距细化不明显,析出相的平均面积分数略增大,细化球化作用减弱,Ti、Cr、Mo和Nb元素偏析程度加剧。因此,需要在N06625合金中添加适量的Mg元素,从而为优化N06625合金提供一定程度的理论参考。N06625 alloy contains a large number of strengthening elements,and solute redistribution and component supercooling will occur during solidification,which will have a significant impact on the microstructure of alloy.The influence of magnesium content on phase transformation behavior and the changes of main elements concentration in the residual liquid phase of N06625 alloy during non-equilibrium solidification was analyzed by Thermo-Calc thermodynamic software,and the effect for different mass fractions of magnesium(0,0.0052%,0.0081%and 0.0250%)on the as-cast structure of N06625 alloy were studied by optical microscope(OM)and field emission scanning electron microscope(FESEM).The results show that the solid-liquid phase temperature range increases with the increase of magnesium content,and the precipitation temperature of each phase is changed,but not the precipitation phase type.With the increase of magnesium content,the concentrations of Ni and Mg elements in the residual liquid phase increase,while the concentrations of Cr,Mo,Nb and C elements decrease.When magnesium is not added,the secondary dendrite spacing is larger,and the precipitated phase precipitates in interdendritic area in the form of strip and block,with larger average area fraction and size.When the mass fraction of magnesium in the alloy increases from 0 to 0.0052%and 0.0081%,the secondary dendrite spacing is refined,the average area fraction of precipitated phase decreases,and refinement and spheroidization effects occur,the distribution is more dispersed and the degree of element segregation for Ti,Cr,Mo and Nb is weakened.When the mass fraction of magnesium increases to 0.0250%,the refinement of the secondary dendrite spacing is not obvious,the average area fraction of precipitated phase increases slightly,the refinement and spheroidization effects decrease and the degree of element segregation for Ti,Cr,Mo and Nb increases.Therefore,it is necessary to add an appropriate amount of magnesium elements to N06625 alloy to provide some degree of

关 键 词：N06625合金 镁处理 二次枝晶间距 析出相 元素偏析 

分 类 号：TG244.3[金属学及工艺—铸造]