(1. 中南大学 粉末冶金研究院，长沙 410083；
(2. 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 通过透射电子显微镜、电子背散射衍射、扫描电子显微镜和室温拉伸检测等手段，建立并验证双模晶粒尺寸分布氧化物弥散强化合金的室温强化预测模型。同时，通过在1150 ℃下进行不同时间的热处理试验，结合组织观察和显微硬度测试，研究合金的高温组织热稳定性。结果表明：室温强化预测模型通过叠加固溶强化(sss)、晶粒尺寸强化(sg)、位错强化(sd)与氧化物纳米粒子强化(sp)之和的平方根，模型预测结果与试验值十分接近。合金组织热稳定性研究结果表明，在1150 ℃热处理初期，晶粒长大迅速且合金硬度迅速降低；而当热处理时间延长到8 h之后，晶粒尺寸虽有变化但其长大速率明显放缓，且合金硬度在热处理8 h后趋于稳定。
关键字: 双模分布；晶粒；氧化物弥散强化；强化模型；热稳定性
（1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
2. State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The yield strength model of oxide dispersion strengthened alloy with a bimodal size distribution of grain was established and verified via transmission electron microscope, electron backscatter diffraction, scanning electron microscope and tensile tests. In addition, the thermal stability of the alloy was investigated by heat treatment experiment, optical microscope observation and Vickers hardness. The results show that the yield strength model can be established by integrating solid solution strengthening (sss), grain size strengthening (sg), dislocation strengthening (sd) and oxide nanoparticle strengthening (sp), and the calculated values fit well with the experimental values. The research on thermal stability shows that the grains grow rapidly and the hardness decreases sharply at the early stage of heat treatment at 1150 ℃. However, after heat treatment for 8 h, the grain growth slows down and the hardness of the alloy keeps stable in response.
Key words: bimodal size distribution; grain; oxide dispersion strengthening; strengthening model; thermal stability
