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研究了Ce含量对铸造态Fe-6.5%Si(质量分数)合金显微组织、有序结构和中温拉伸性能的影响,分析了Ce微合金化改善合金塑性的机理。结果表明,Ce含量在150×10~(-6)以下时,合金铸造组织无明显变化;Ce含量在210×10~(-6)以上时,铸造组织明显细化。Ce的添加可大幅度降低合金的有序程度,显著改善中温拉伸塑性;当Ce含量为62×10~(-6)、150×10~(-6)和210×10~(-6)时,400℃拉伸试样的平均断后伸长率由无Ce试样的7.4%分别升高至10.1%、19.3%和23.0%;而Ce含量增加至260×10~(-6)和790×10~(-6)时,Ce在晶界明显富集导致试样拉伸断口呈现沿晶脆断特征,平均断后伸长率下降至15.5%和14.2%。有效改善Fe-6.5%Si合金塑性的合适Ce含量范围为(150~210)×10~(-6)。
The effects of Ce content on the microstructure, ordered structure and tensile properties at mid-temperature of Fe-6.5% Si alloy were investigated. The mechanism of Ce microalloying to improve the plasticity of the alloy was also studied. The results show that the microstructure of the alloy has no obvious change when the content of Ce is less than 150 × 10 ~ (-6). When the content of Ce is above 210 × 10 ~ (-6), the microstructure of the alloy is obviously refined. The addition of Ce can greatly reduce the degree of orderliness of the alloy and significantly improve the ductility at medium temperature. When the content of Ce is 62 × 10 -6, 150 × 10 -6 and 210 × 10 -6, , The average elongation at break after 400 ℃ tensile test increased from 7.4% without Ce to 10.1%, 19.3% and 23.0% respectively, whereas the Ce content increased to 260 × 10 -6 and 790 × 10 ~ (-6), the obvious enrichment of Ce in the grain boundaries led to the brittle fracture along the grain boundaries, and the average elongation at break decreased to 15.5% and 14.2%, respectively. The suitable Ce content for improving the plasticity of Fe-6.5% Si alloy is (150 ~ 210) × 10 -6.