【摘要】 研究了冷速对LaFe_12.4-xSi_xCo_0.6合金的凝固行为的影响。应用XRD和SEM扫描电镜分析了合金显微组织结构和相组成,并应用包晶凝固理论对此作了进一步的解释。结果表明,冷速和Si含量变化对合金的凝固行为有很大的影响。冷速较低约为60 K/s,x≤1.5时凝固组织以Fe相为主;随冷速增加约为500 K/s,x=1.5时,合金的凝固组织出现1∶13相;随冷速的进一步增加约为1 500 K/s,x=1.0时出现1∶13相,且随x值增加1∶13相含量增加。更多还原

【Abstract】 The effect of cooling rate on solidification behavior of LaFe_12.4-xSi_xCo_0.6 alloys was investigated. Phase formation and microstructure of LaFe_12.4-xSi_xCo_0.6 alloys had been investigated by means of power X-ray diffraction analysis（XRD） and scanning electron microscopy（SEM）. The reasons were discussed within the framework of the theories on crystal nucleation. The results shown that the solidification behavior of LaFe_12.4-xSi_xCo_0.6 alloys depend on cooling rate and Si content. When the cooling rate is about 60 K/s, the microstructure of the sample is consistent of α-Fe dendrites and in interdendritic eutectic 1 ∶1∶1 phase. α-（Fe,Si） phase is primary phase. When 500 K/s, the microstructure of the sample is made of α-Fe dendrites and in interdendritic 1∶13 phase and 1∶1∶1 phase. When 1 500 K/s and x=1.0, the microstructure of the sample occur 1∶13 phase. The 1∶13 phase increase with x increasing.更多还原