Bachmaier A, Motz C
Chair of Materials Science and Methods, Saarland University, Saarbrücken, Germany.
Mater Sci Eng A Struct Mater. 2015 Jan 29;624:41-51. doi: 10.1016/j.msea.2014.11.062.
Nanostructured Co materials are produced by severe plastic deformation via alloying with small amounts of C and larger amounts of Cu. The thermal stability of the different nanostructured Co materials is studied through isothermal annealing at different temperatures for various times and compared to the stability of severe plastically deformed high-purity nanocrystalline Co. The microstructural changes taking place during annealing are evaluated by scanning electron microscopy, transmission electron microscopy and microhardness measurements. In the present work it is shown that the least stable nanostructured material is the single-phase high purity Co. Alloying with C improves the thermal stability to a certain extent. A remarkable thermal stability is achieved by alloying Co with Cu resulting in stabilized nanostructures even after annealing for long times at high temperatures. The essential reason for the enhanced thermal stability is to be found in the immiscibility of both components of the alloy.
通过与少量碳和大量铜合金化，利用严重塑性变形制备出纳米结构钴材料。通过在不同温度下进行不同时间的等温退火，研究了不同纳米结构钴材料的热稳定性，并与严重塑性变形的高纯度纳米晶钴的稳定性进行了比较。通过扫描电子显微镜、透射电子显微镜和显微硬度测量来评估退火过程中发生的微观结构变化。在本工作中表明，最不稳定的纳米结构材料是单相高纯度钴。与碳合金化在一定程度上提高了热稳定性。通过将钴与铜合金化，即使在高温下长时间退火后也能形成稳定的纳米结构，从而实现了显著的热稳定性。合金热稳定性增强的根本原因在于合金两种成分的不混溶性。
