Ductile-brittle transition temperature (DBTT) is a critical property of tungsten (W) materials for their application in a fusion reactor. The mechanism of ductile-brittle transition (DBT) has been the focus of debate in past decades. In this work, four-point bending test (4PBT) was performed to explore the controlling factors in different directions relative to the rolling direction. Opposite DBTT shifting trend in different directions after different recrystallization treatments indicated the diverse controlling factors of DBTT in rolled-W. Combined with microstructure analyses, the dislocation activity is considered the main controlling factor of DBTT in parallel to the rolling direction. For the samples perpendicular to the rolling direction, the change of DBTT is strongly correlated with the fracture mode. This study revealed the controlling factor of DBTT is anisotropic related to rolling direction after different recrystallization treatments.

韧脆转变温度 (DBTT) 是钨 (W) 材料在聚变反应堆中应用的关键特性。韧脆转变（DBT）的机制一直是过去几十年争论的焦点。在这项工作中，进行了四点弯曲试验（4PBT）以探索相对于轧制方向不同方向的控制因素。不同再结晶处理后DBTT在不同方向上的相反移动趋势表明DBTT在轧制W中的控制因素不同。结合显微组织分析，位错活动被认为是平行于轧制方向的DBTT的主要控制因素。对于垂直于轧制方向的试样，DBTT的变化与断裂模式密切相关。