Effect of heat treatment on the hardness and microstructure in Co–3Al–1.5Y2O3–1.2Hf ODS alloy
Effect of heat treatment on the hardness and microstructure in Co–3Al–1.5Y2O3–1.2Hf ODS alloy
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DOI：
10.1016/j.msea.2014.02.009
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发表时间：
2014-04
期刊：
影响因子：
6.4
通讯作者：
T. Sasaki;K. Takezawa;S. Ukai;N. Oono;S. Hayashi
中科院分区：
文献类型：
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作者：
T. Sasaki;K. Takezawa;S. Ukai;N. Oono;S. Hayashi
采用机械合金化(MA)和放电等离子烧结(SPS)相结合的方法制备了氧化物弥散强化钴基合金。烧结体由硬质区和软质区组成。硬质区由纳米晶fcc-Co(γ-Co)颗粒组成，纳米氧化物颗粒弥散分布，软区存在粗大的ε-Co(hcp-Co)和fcc-Co颗粒。纳米晶组织和氧化物颗粒在硬质区的弥散分布归因于烧结态样品中410VHN的高硬度。在1000℃、240℃、240℃等温退火后仍能保持较高的硬度，表明由于氧化物颗粒的晶界钉扎作用，细晶组织具有良好的稳定性。
An oxide dispersion strengthened (ODS) Co-based alloy was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The sintered sample consisted of hard and soft regions. The hard region consisted of nanocrystalline fcc-Co (γ-Co) grains with the dense dispersion of nano-scale oxide particles, and coarse hcp-Co (ε-Co) and fcc-Co grains were present in the soft region. The nanocrystalline grain structure and oxide particle dispersion in the hard region is attributed to the high hardness of 410 VHN in the as-sintered sample. The high hardness was maintained after annealing at 1000 °C for 240 h indicating the excellent stability of the fine grain structure due to the grain boundary pinning by the oxide particles.