It is very well known that tungsten is intrinsically brittle at room temperature, and the characterization of its ductile properties by conventional mechanical tests is possible only above the ductile-to-brittle transition temperature (DBTT), i.e. above 500–700 K. However, the design of tungsten-based components often requires the knowledge of constitutive laws below the DBTT. Here, we carried out instrumented hardness measurements in the temperature range of 300–691 K by nano-indentation. The obtained results are used to extend a set of constitutive laws for the plastic deformation of tungsten, developed earlier on the basis of tensile data, which now covers the temperature range of 300–1273 K. The validation of the constitutive laws was realized by the crystal plasticity finite element method (CPFEM) model, which was applied to simulate the nano-indentation loading curves. The distribution of stress and strain under the indenter was also studied by the CPFEM to bring an insight on the extension of the plastic zone in the process of the indentation, which is of crucial importance when nano-indentation is used to resolve the microstructural features generated by e.g. irradiation by energetic particles, plasma exposure or thermo-mechanical treatment.

众所周知，钨在室温下本质上是脆性的，只有通过在韧性到脆性转变温度（DBTT）以上（即高于500-700 K），才能通过常规机械测试表征钨的延性。钨基组件的设计通常需要了解DBTT以下的本构定律。在这里，我们通过纳米压痕在300–691 K的温度范围内进行了仪器硬度测量。获得的结果用于扩展钨的塑性变形的本构定律，该定律是根据拉伸数据在较早的基础上开发的，现在覆盖了300–1273 K的温度范围。晶体可塑性有限元方法（CPFEM）模型，它被用来模拟纳米压痕载荷曲线。CPFEM还研究了压头下的应力和应变分布，以了解压痕过程中塑性区的延伸，这在使用纳米压痕解决所产生的微观结构特征时至关重要。通过例如高能粒子的照射，等离子体暴露或热机械处理。