双模晶粒氧化物弥散强化合金的强化模型及热稳定性

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(σss)、晶粒尺寸强化(σg)、位错强化(σd)与氧化物纳米粒子强化(σp)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。

Strengthening model and thermal stability of anoxide dispersion strengthened alloy with bimodal size distribution of grains

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(σss),grain size strengthening(σg),dislocation strengthening(σd)and oxide nanoparticle strengthening(σp),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.