Fe-C nanograined alloys obtained by high-pressure torsion: Structure and magnetic properties
Fe-C nanograined alloys obtained by high-pressure torsion: Structure and magnetic properties
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DOI：
10.1016/j.msea.2008.03.052
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发表时间：
2009-03
期刊：
影响因子：
6.4
通讯作者：
B. Straumal;A. Mazilkin;S. Protasova;S. Dobatkin;A. Rodin;B. Baretzky;D. Goll;G. Schütz
中科院分区：
文献类型：
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作者：
B. Straumal;A. Mazilkin;S. Protasova;S. Dobatkin;A. Rodin;B. Baretzky;D. Goll;G. Schütz
本文研究了碳含量在0.05 ~ 1.7wt.%之间的九种二元Fe-C合金的显微结构、相组成、穆斯堡尔谱和磁性能在铸态下，在725°C下长时间退火后，以及在环境温度和5GPa下用5次砧旋转（剪切应变约6）进行高压扭转（HPT）后，研究了HPT后的晶粒尺寸在纳米范围内。热处理后，合金中只剩下Fe_3C（Al_2O_3）和α-Fe。结果还表明，不太稳定的Hägg碳化物（Fe_5C_2）和残余奥氏体消失，相组成接近对应于HPT温度和压力的平衡。饱和磁化强度和穆斯堡尔效应的测量结果表明，HPT后，铁的量减少。铁素体部分溶解的原因是铁素体晶界富碳偏析层的形成。
The microstructure, phase composition, Mössbauer spectra and magnetic properties of nine binary Fe–C alloys with carbon concentrations between 0.05 and 1.7wt.% were studied in the as-cast state, after a long annealing at 725°C and after high-pressure torsion (HPT) at ambient temperature and 5GPa with five anvil rotations (shear strain about 6). The grain size after HPT was in the nanometer range. Only Fe3C (cementite) and α-Fe remain in the alloys after HPT. It was also shown that the less stable Hägg carbide (Fe5C2) and retained austenite disappear, and phase composition closely approaches the equilibrium corresponding to the HPT temperature and pressure. Measurements of saturation magnetization and Mössbauer effect reveal that the amount of cementite decreases after HPT. The reason for partial cementite dissolution is the formation of the carbon-rich segregation layers in the ferrite grain boundaries.