添加Ti对Fe-4%Si合金凝固组织的影响及机理  

Effect of Adding Ti on Solidification Structure of Fe-4%Si Alloy and Its Mechanism

作　　者：白慧怡 计云萍[1,2] 李一鸣 任慧平 BAI Huiyi;JI Yunping;LI Yiming;REN Huiping(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China;Key Laboratory of Advanced Metal Material of Inner Mongolia Autonomous Region,Baotou 014010,China;Analytical and Testing Center of Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,包头014010 [2]内蒙古自治区新金属材料重点实验室,包头014010 [3]内蒙古科技大学分析测试中心,包头014010

出　　处：《材料导报》2021年第20期20119-20123,共5页Materials Reports

基　　金：国家自然科学基金(51761034)。

摘　　要：选用能将初生δ-铁素体保留至室温的Fe-4%Si合金,通过对比添加Ti与不加Ti的合金铸锭的宏观组织,研究添加Ti对Fe-4%Si合金凝固组织的细化作用。采用SEM+EDS对含Ti合金中Ti化合物相进行观察表征,并利用EBSD结合能谱分析对其进行相鉴定。利用边-边匹配(E2EM)模型计算TiN与δ-Fe之间的原子匹配错配度,预测两者之间的位向关系,从晶体学角度探讨TiN对δ-Fe异质形核的效用,并分析Ti的溶质作用。结果表明,添加0.065%Ti使Fe-4%Si合金凝固组织中的柱状晶全部变为等轴晶,添加Ti原位形成的TiN能够作为Fe-4%Si合金凝固时δ-铁素体异质形核的有效核心,TiN的异质形核作用及Ti的溶质作用使柱状晶全部变为等轴晶,有效细化了Fe-4%Si合金的凝固组织。AFe-4%Si alloy was selected to investigate the effect of Ti addition on the refinement of the structure during solidification for it can retain the primaryδ-ferrite to room temperature after solidification.The macrostructures of the Fe-4%Si alloys with and without Ti addition were observed through a digital camera.The Ti-containing compounds were examined using a scanning electronic microscope(SEM)equipped with energy-dispersive X-ray spectroscopy(EDS).The phase identifications of the Ti-containing compounds were conducted by combining the electron backscatter diffraction(EBSD)with the EDS.To evaluate the possibility and the potency of the heterogeneous nucleation ofδ-ferrite on the TiN particles with high melting points from the crystallographic point view,the edge-to-edge matching(E2EM)model was used to calculate the atomic matching mismatch between the TiN particles andδ-ferrite and predict the orientation relationship between them.The solute effect of Ti on the grain refinement of Fe-4%Si alloy was theoretically discussed.The results show that the columnar structures in the Fe-4%Si alloy as-cast changed to total equiaxed crystals through addition of 0.065%Ti.The combination of the heterogeneous nucleation ofδ-ferrite on the in-situ formed TiN and the solute action of Ti resulted in the transformation of columnar structures to equiaxed crystals in Fe-4%Si alloy during solidification.The solidification microstructure of Fe-4%Si alloy is effectively refined.

关 键 词：TI Δ-铁素体 凝固细化 异质形核 溶质作用 

分 类 号：TG111.4[金属学及工艺—物理冶金]