镍基单晶高温合金γ’颗粒[111]取向加载的粗化趋势

针对镍基单晶高温合金的服役条件和机构特点,对γ’颗粒在[111]取向加载时的定向粗化趋势进行了比较系统的研究.通过实验得到镍基单晶高温合金在[111]取向上受载时,γ’颗粒没有表现出沿任何方向上的定向粗化趋势,只是以毛细驱动方式各向同性长大.经过有限元计算表明,外应力作用使各类基体通道中的应力分布具有强烈的各向异性,而在粗化过程中扩展的通道都是Von Mises应力高的通道,而逐渐减小的通道都是Von Mises应力低的通道,这表明塑性变形及其不均匀分布起关键作用.

Directional coarsening trend of γ'-grains of nickel-base single crystal super-alloy under load in [111] orientation

According to the service conditions and structural characteristics of nickel-base single crystal super-alloy, the trend of directional coarsening of γ'-grains under the load in the [111] orientation was systematically studied experimentally. The results showed that no trend of any directional coarsening of γ'-grains occurs but they are just growing isotropically by capillarity. FEM calculation showed that the applied stress makes the stress distribution in various matrix channels strongly anisotropic. However, all the channels extended in coarsening process are those where the Von Mises stress is high, while all the channels narrowed gradually are those where the Von Mises stress is low. Such results illustrated that the plastic deformation and its non-uniform distribution play a significant role.