Abstract:Grain boundary character distribution (GBCD) of the hot isostatic pressed (HIPed) beryllium was systematically analyzed by Electron backscatter diffraction (EBSD), and the pressureless sintered beryllium was prepared for making a comparison. It is discovered that some grains of the HIPed beryllium has very dense low angle grain boundaries (LAGBs) of 2°-5° and a large number of fine-grains within grain interiors. The size of fine-grains is mostly in the range of hundreds of nanometers. Conversely, the pressureless sintered beryllium has few LAGBs and no fine-grains. The results show that the beryllium which has very high stacking fault energy not only takes place dynamic recovery (DRV) during HIPing, but also enables access to dynamic recrystallization (DRX). It is very unique that the dynamic recrystallization behavior of the metal beryllium during HIPing. A large number of recrystallized grains are densely formed within grains interior at the same time, but they have a specific orientation relationship with the beryllium matrix. The specific disorientations are 29°<2 0>/<0001>, 59°<2 0>, 74°<2 0> or 78°<2 11>/<10 0>, and 88°<2 0>/<10 0>, respectively. The disorientations can be divided into two categories according to their characteristic. One is that its disorientation axis is the slip direction of beryllium, and the other is the low Σ value coincidence site lattice (CSL) grain boundaries of beryllium, in which 59°<2 0> and 74°<2 0> disorientations are both. The highly efficient recovery and recrystallization of beryllium powder sintered body during HIPing to acquire more optimized dislocation configurations is the prerequisites for the HIPed beryllium to achieve high ductility. Increasing the hot isostatic pressing temperature is able to effectively promote the dynamic recovery and recrystallization of beryllium powder sintered body during HIPing, and thus the ductility of the HIPed beryllium is improved.