硼化物、富Ce混合稀土对再生Al-Si合金中富铁相变质行为的研究

Effects of borides and Ce-rich Mischmetal on the modification of Fe-rich intermetallics in secondary Al-Si alloys

摘要:

本文研究了硼化物、富Ce混合稀土对再生Al-Si合金富铁相变质行为的影响。采用光学显微镜（OM）、扫描电镜（SEM）对试样微观组织进行形貌观察，采用X射线衍射仪分析仪（XRD）、扫描电镜附带的能谱仪（EDS）分别对试样进行相分析与相成分分析，利用差分扫描量热仪（DSC）研究相转变温度。研究表明硼化物可以促进针状β-Fe相向初生α-Fe相转变，且初生α-Fe相尺寸随着硼化物的添加量增加而增大，当硼化物（KBF4）添加量达到1.0%时，开始析出汉字状α-Fe相，汉字状α-Fe相以初生α-Fe相为基底形核并长大；富Ce混合稀土可以抑制初生α-Fe相长大，且能抑制汉字状α-Fe相生成

Abstract:

Effects of borides and Ce-Rich mischmetal on the modification of Fe-rich intermetallics in secondary Al-Si alloys are studied in this paper.Microstructure morphology is observed by optical microscope(OM) and scanning electric microscope(SEM) , phases and compositions of phases are analyzed by X-ray diffraction(XRD)and energy dispersive X-ray (EDS) respectively.Phase transition temperature is measured by differential scanning calorimeter(DSC).It is indicated that borides can prompt transformation from needle-like β-Fe phase to primary α-Fe phase. And the size of primary α-Fe phase increases with the addition of borides. When the borides（KBF4）reaches 1.0%, Chinese script-type α-Fe phase begins to precipitate. Nucleation of Chinese script-type α-Fe phase are based on primary α-Fe phase. Ce-rich mischmetal can inhibit the growth of the primary α-Fe phase and the formation of Chinese script-type α-Fe phase.