不同应变速率热变形双相不锈钢的取向特征

在MMS-200热模拟实验机上,对S32750超级双相不锈钢在1 000℃,应变速率为0.01～10 s-1的条件下进行了高温压缩实验,利用电子背散射衍射(EBSD)技术对其晶体取向和晶界特征进行了分析.研究结果表明:在低应变速率时,铁素体晶粒出现〈111〉∥压缩轴织构;在高应变速率时,〈001〉织构又明显增加.铁素体晶粒随着应变速率的增加变得细小,而小角度晶界数量增加;在应变速率为10 s-1时,形变后奥氏体晶粒得到了〈110〉织构.应变速率的增加使奥氏体晶粒变大,小角度晶界数量增加.奥氏体相在小应变速率条件下变形可以获得更多的Σ3孪晶界.

Orientation Characteristics of Hot Deformed Duplex Stainless Steel Under Different Strain Rate

Under 1000°C and strain rate range of 0.01~10 s^-1, the hot compression test of super duplex stainless steels S32750 was carried out with MMS-200 thermal-mechanical simulator. EBSD(electron backscattering diffraction) technique was applied to analyze grain orientation and grain boundary characters. The results showed that the <111> texture appears in ferrite under lower strain rate, and the additional <001> texture appears under higher strain rate. The ferrite grains become finer and the number of small angle grain boundaries increases with the increasing of strain rate. The <110> texture appears in the deformed austenite under the strain rate of 10 s^-1. The austenite grain size and the number of small angle grain boundaries increase with the increasing of strain rate. A lot of Σ3 twin boundaries appear in the deformed austenite under lower strain rate.