(1. 中南大學(xué) 粉末冶金研究院，長沙 410083；
(2. 中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 通過透射電子顯微鏡、電子背散射衍射、掃描電子顯微鏡和室溫拉伸檢測等手段，建立并驗證雙模晶粒尺寸分布氧化物彌散強化合金的室溫強化預(yù)測模型。同時，通過在1150 ℃下進行不同時間的熱處理試驗，結(jié)合組織觀察和顯微硬度測試，研究合金的高溫組織熱穩(wěn)定性。結(jié)果表明：室溫強化預(yù)測模型通過疊加固溶強化(sss)、晶粒尺寸強化(sg)、位錯強化(sd)與氧化物納米粒子強化(sp)之和的平方根，模型預(yù)測結(jié)果與試驗值十分接近。合金組織熱穩(wěn)定性研究結(jié)果表明，在1150 ℃熱處理初期，晶粒長大迅速且合金硬度迅速降低；而當熱處理時間延長到8 h之后，晶粒尺寸雖有變化但其長大速率明顯放緩，且合金硬度在熱處理8 h后趨于穩(wěn)定。
關(guān)鍵字: 雙模分布；晶粒；氧化物彌散強化；強化模型；熱穩(wěn)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
