Hardness loss and microstructure evolution of 90% hot-rolled pure tungsten at 1200–1350 °C

• DOI: 10.1016/j.fusengdes.2017.05.072
• Publication Date: 2017-05-22T23:30:39Z
• Authors: Ming Yu; Kang Wang; Xiang Zan; Wolfgang Pantleon; Laima Luo; Xiaoyong Zhu; Yucheng Wu
• Keywords: Recrystallization (geology); Vickers hardness test; Isothermal process

Abstract Tungsten is a promising plasma-facing material because of its low sputtering yield, high melting point and high thermal conductivity. The hardness loss and microstructure evolution of pure tungsten hot-rolled to 90% thickness reduction is investigated by isothermal annealing at temperature range of 1200–1350 °C. Changes in the mechanical properties caused by recovery and recrystallization during heat treatment are detected by Vickers hardness measurements. Additionally, the microstructural evolution is analyzed with light optical microscopy and X-ray diffraction. The results indicate that the hardness evolution can be divided into two stages: recovery and recrystallization. Recrystallization of W90 in the temperature range of 1200 to1350 °C is governed by the same activation energy as grain boundary diffusion. The average recrystallized grain size is larger for lower annealing temperatures.