High-temperature grain size stabilization of nanocrystalline Fe-Cr alloys with Hf additions

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:613

Article

Li, Lulu¹  Saber, Mostafa¹  Xu, Weizong¹  Zhu, Yuntian¹  Koch, Carl C.¹  Scattergood, Ronald O.¹ 

[1] N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA

关键词: Mechanical alloying;    Nanocrystalline Fe-Cr alloys;    Grain growth;    Thermal stability;   

DOI  :  10.1016/j.msea.2014.06.099

来源: Elsevier

【 摘 要 】

The influence of 1-4 at%, Hf additions on the thermal stability of mechanically alloyed nanocrystalline Fe-14Cr alloys was studied in this work. XRD-calculated grain size and microhardness results were reported versus isochronal annealing treatments up to 1100 degrees C Microstructural evolution was investigated using channeling contrast FIB imaging and TEM. Grain size of samples with 4 aft Hf was found to be maintained in the nanoscale range at temperatures up to 1000 degrees C Zener pinning was considered as a major source of high temperature grain size stabilization. By comparing the Orowan strengthening contribution to the total hardness, the deviation of grain size predictions from the actual grain size in Fe-14Cr-4Hf suggests the presence of thermodynamic stabilization by the solute segregation to grain boundaries (GBs). A predictive thermodynamic model indicates that the thermodynamic stabilization can be expected. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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