退火温度对镍基ODS合金组织结构的影响

The influence of annealed temperature on microstructure in nickel-based ODS alloy

摘要:

应用于核反应堆和航空航天领域的镍基ODS合金，在加工成型和热处理过程中，晶界会发生迁移，导致合金中的纳米氧化物颗粒溶解再析出或通过Ostwald熟化使纳米氧化物发生长大，使合金中氧化物颗粒尺寸增加、数密度降低，从而影响合金的力学性能。本文对冷变形后镍基ODS合金进行不同温度的退火，通过TEM、XRD和EBSD分析了合金的微观组织结构，探究了退火工艺对冷变形后镍基ODS合金微观组织结构的影响。结果表明：随着退火温度的升高，镍基ODS合金的位错密度减少，少量纳米氧化物颗粒发生粗化；冷变形态合金经过900 ℃退火后，组织均匀且纳米氧化物颗粒未发生明显长大；通过计算，确认了900 ℃退火后镍基ODS合金拉伸性能的主要贡献为位错强化和弥散强化，为合金性能的提升提供理论支撑和有效手段。

Abstract:

The nickel-based ODS alloy could be applied to nuclear reactor and aerospace. The dissolution and precipitate of the oxide particles or the Ostwald repining in the nickel-based ODS alloy resulting from the grain boundary migration affect the mechanical properties of the nickel-based alloy by increasing the size and decreasing the number density of the oxide particles during the cold working and heat treatment. In this paper, the microstructure of the cold-rolled nickel-based ODS alloy annealing at different temperature were characterized by XRD, EBSD, and TEM. The influence of the annealing process on the microstructure of the cold-rolled nickel-based ODS alloy was studied. It is indicated that the dislocation density of the nickel-based ODS alloy decreased and part of the oxide particle coarsened with the annealed temperature rising. Besides, there were the uniform microstructure and the fine oxide particles in the nickel-based ODS alloy after annealing at 900 ℃. According to the calculation, the tensile strength of the nickel-based ODS alloy after annealing at 900 ℃ is mainly contributed by the dispersion strengthening and dislocation strengthening which were the theoretical basis and the effective method to improving the properties of the nickel-based ODS alloy.