Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第21卷    第6期    总第147期    2011年6月

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文章编号:1004-0609(2011)06-1396-08
球磨法制备Fe-1%C纳米晶及其热稳定性
张  柯,刘  峰, 宫明明,杨根仓

(西北工业大学 凝固技术国家重点实验室,西安 710072)

摘 要: 采用机械球磨方法制备了Fe-1%C(摩尔分数)单相固溶体纳米晶粉体材料,通过扫描电镜(SEM)及X射线衍射仪(XRD)分析球磨时间对粉末形貌和晶粒尺寸的影响,应用Scherrer公式得出平均晶粒尺寸与球磨时间的关系。结果表明:在球磨机主转速为155 r/min条件下,球磨10 h时,得到Fe-C单相固溶体;球磨时间达到85 h以上时,合金粉末形貌及尺寸趋于稳定,晶粒尺寸稳定在8 nm左右。由于大量晶界以及微观应变的存在,获得的Fe-C纳米晶具有自发长大趋势。采用差热分析(DSC)手段研究不同等温条件下Fe-C纳米晶的热稳定性,结合晶粒长大热力学和动力学理论,求得晶界扩散激活能及稳定晶粒尺寸等参数,并分析讨论Fe-C纳米晶的晶粒稳定机制。

 

关键词: Fe-C合金;纳米晶;稳定性;机械球磨

Preparation of Fe-1%C nanocrystalline by
mechanical milling and its thermal stability
ZHANG Ke, LIU Feng, GONG Ming-ming, YANG Gen-cang

State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China

Abstract:The particles of Fe-1%C (mole fraction) alloy with the single phase solid solution nanocrystalline were produced by mechanical milling. The influences of milling time on the particles morphologies and the grain size were investigated by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Applying Scherrer formula, the average grain size, furthermore, the grain size evolution with the milling time, was obtained. The results show that the single phase solid solution has already been achieved after 10 h milling. Both the particles morphologies and the grain size become stable after milling over 85 h, and the final grain size is about 8 nm. The Fe-C nanocrystallines have the tendency of growing up resulting in the large amount of grain boundaries and micro-strain among them. The thermal stability of Fe-C nanocrystalline at different temperatures was investigated by isothermal differential scanning calorimetry (DSC) technology. Combining with the thermodynamics and kinetics of grain growth, the active energy of grain boundary diffusion and the stable grain size were calculated, and the stable mechanism of Fe-C nanocrystalline was discussed.

 

Key words: Fe-C alloy; nanocrystalline; thermal stability; mechanical milling

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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