Creep properties and microstructure of a precipitation-strengthened ferritic Fe-Al-Ni-Cr alloy
Creep properties and microstructure of a precipitation-strengthened ferritic Fe-Al-Ni-Cr alloy
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DOI：
10.1016/j.actamat.2014.02.020
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发表时间：
2014-06-01
期刊：
影响因子：
9.4
通讯作者：
Dunand, David C.
中科院分区：
文献类型：
--
作者：
Vo, Nhon Q.;Liebscher, Christian H.;Dunand, David C.
铁素体合金Fe-10Cr-10Ni-5.5Al-3.4Mo-0.25Zr-0.005B(wt.%)由体积分数为13%、平均析出半径为62 nm的共格B2结构(Ni，Fe)Al相强化，在30-300 MPa应力范围和600-700℃温度范围内蠕变。稳态应变速率与应力的关系可用高视应力指数为6-13和高表观激活能为510-680kJ·mol(-1)的幂规律来表示。在所研究的所有温度下观测到的门槛应力范围为69~156 Mpa，由此确定的真应力指数接近于4，真激活能为243+/-37kJ mol(-1)，分别相当于位错蠕变和晶格扩散的激活能。基于这些力学结果和详细的电子显微镜观察，蠕变机制被合理地归结为总体位错攀移，共格析出物与基质位错之间存在排斥弹性相互作用。(C)2014 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
The ferritic alloy Fe-10Cr-10Ni-5.5Al-3.4Mo-0.25Zr-0.005B (wt.%), strengthened by coherent B2-structured (Ni,Fe)Al precipitates with a volume fraction of 13 vol.% and average precipitate radius of 62 nm, was subjected to creep in the stress range 30-300 MPa and the temperature range 600-700 degrees C. The stress dependence of the steady-state strain rate can be represented by a power law with high apparent stress exponents of 6-13 and high apparent activation energies of 510-680 kJ mol(-1). Threshold stresses at all studied temperatures were observed, ranging from 69 to 156 MPa, from which a true stress exponent of similar to 4 and a true activation energy of 243 +/- 37 kJ mol(-1) were determined, which are equal to those for dislocation creep and lattice diffusion in the ferritic matrix, respectively. Based on these mechanical results and detailed electron microscopy observations, the creep mechanism was rationalized to be general dislocation climb with repulsive elastic interaction between coherent precipitates and the matrix dislocations. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.