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氮气氛下多孔纯铁的区熔法制备技术研究
Study on Preparation Technology of Porous Pure Iron by Zone Melting in Nitrogen Atmosphere 在线阅读 下载PDF
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- DOI:
- 作者:
- 刘恩典 李再久 刘沉 金青林
LIU Endian;LI Zaijiu;LIU Chen;JIN Qinglin
- 作者单位:
- 昆明理工大学材料科学与工程学院 昆明理工大学民航与航空学院
Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Faculty of Civil Aviation and Aeronautics,Kunming University of Science and Technology,Kunming 650500,China
- 关键词:
- 双尺度气孔 区域熔炼法 多孔铁 氮气氛
double-scale pores zone melting method porous iron nitrogen atmosphere
- 摘要:
- 以氮气代替安全隐患巨大的氢气作为工作气体,用区域熔炼方法成功制备了藕状多孔纯铁。结果表明,除宏观柱形孔(150-600 μm)外,在显微组织中发现分布均匀的球型孔(0.15〜12.00 μm),气压的增大使球型孔直径减小、数目增多。由Fe-N相图可知,纯铁的凝固及随后的冷却过程中存在着两个较大的氮溶解度差。圆柱形孔是由液相向固相转变时过饱和氮气的析出造成的,球型孔的形成则归因于奥氏体向低温铁素体转变时的氮溶解度差。基于西华特定律和理想气体公式,建立了两种尺度气孔率的模型,模型预测值与实验测量值吻合良好。
Lotus-type porous pure iron was successfully prepared by zone melting method with using nitrogen instead of hydrogen as working gas. The results show that in addition to the macro cylindrical pores(150~600 μm), uniform spherical pores(0.15~12.00 μm) are found in the microstructure. The diameter of spherical pores decreases and the number of spherical pores increases with the increase of pressure. The phase diagram of Fe-N indicates that there are two significant differences in nitrogen solubility during solidification and subsequent cooling of pure iron. The cylindrical pores are caused by the precipitation of susaturated nitrogen during the transition from liquid to solid phase, and the spherical pores are caused by the poor nitrogen solubility during the transition from austenite to low temperature ferrite. Based on Sewert’s law and ideal gas formula, two kinds of porosity models are established, and the predicted values are in good agreement with the experimental measured ones.