9Mn27Al10Ni3Si低密度钢的高温压缩变形行为及其机制

使用Gleeble热模拟试验机、XRD、OM、SEM和TEM等手段研究了9Mn27Al10Ni3Si低密度钢在850~1050℃和0.01~5 s^-1条件下的热压缩变形特征及其机制。结果表明，对这种钢在850~950℃进行低应变速率(0.01~1 s^-1)热压缩时，κ-碳化物的析出和粗化以及在热压缩过程中摩擦系数的增大使其应变达到临界值后流变应力明显增大；随着应变速率的提高，实验钢的孪生显著增强，显著加快了奥氏体的动态再结晶过程，使其在高应变速率热压缩时动态再结晶的程度比低应变速率压缩时更为显著。再结晶的软化作用，使上述流变应力异常增大的现象逐渐减弱甚至消失。

High Temperature Compression Deformation Behavior of 9Mn27Al10Ni3Si Low Density Steel

The deformation characteristics of 9Mn27Al10Ni3Si low density steel at 850~1050℃ with strain rate within the range of 0.01~5 s^-1 were investigated by using Gleeble thermal simulator, XRD, OM, SEM and TEM. The results show that when the steel is hot compressed at 850~950℃ with low strain rate (0.01~1 s^-1), the flow stress of the steel increases obviously as the strain reaches a certain critical value, which may be due to the precipitation and coarsening of κ-carbides, and the increase of friction coefficient of the steel during hot compression. With the increase of strain rate, the number of twins increases significantly, which can speed up the process of dynamic recrystallization of austenite, however, during thermal compression by high strain rate, the dynamic recrystallization process is more significant rather than by low strain rate. Due to the softening effect of recrystallization, the abnormal rise of flow stress gradually weakens or even disappears.