Extending the lifetime of tungsten based plasma facing components for future fusion reactors remains an everlasting challenge. In this work, the microstructure of tungsten monoblocks exposed to a few thousand cycles of combined pulsed heat loads of 10 and 20 MWm⁻² (achieved via an electron beam) is thoroughly investigated. The heat exposure assisted surface roughening is observed to be significant. Build-up of thermal stresses in the monoblock results in severe geometrical distortions. The evolution of the microstructure of the tungsten monoblocks due to recrystallization is found to be substantial in the top 5.5 mm from the surface, and the relation between the recrystallization threshold and temperatures throughout the monoblock is investigated. Additionally, no traces of recrystallization-induced crack formation within the monoblock is observed. The recrystallization-induced microstructural evolution is investigated in terms of grain size, grain boundary distribution, and the recrystallization induced softening as determined from micro-hardness measurements. An adequate quantitative match between the changes in the microstructural features such as grain size, grain boundary character, and the related hardness is obtained. Moreover, the depth dependent microstructural recrystallized fraction in the monoblock is examined via hardness and EBSD measurements, and a comparison between the different methods is presented. The presence of a preferred crystal orientation of the recrystallized grains is observed and discussed in terms of the initial texture.

对于未来的聚变反应堆而言，延长钨基等离子体面对部件的寿命仍然是一个永恒的挑战。在这项工作中，钨单体的微结构暴露于数千个10和20 MWm ^-2的组合脉冲热负荷循环中（通过电子束实现）已被彻底研究。观察到热辅助的表面粗糙化是显着的。整体中热应力的积累会导致严重的几何变形。发现从重结晶开始，钨单嵌段的微观结构在距表面的顶部5.5 mm处相当大，并且研究了重结晶阈值与整个单嵌段的温度之间的关系。另外，在单体中没有观察到再结晶引起的裂纹形成的痕迹。根据晶粒尺寸，晶界分布和由显微硬度测量确定的由再结晶引起的软化，研究了由再结晶引起的微结构演变。在微观结构特征的变化（例如晶粒尺寸，晶界特征和相关硬度）之间获得了足够的定量匹配。此外，通过硬度和EBSD测量检查了单体中深度依赖的微结构重结晶部分，并给出了不同方法之间的比较。根据初始织构观察并讨论了重结晶晶粒的优选晶体取向的存在。