Establishment of processing map and analysis of microstructure on multi-crystalline tungsten plastic deformation process at elevated temperature

• Dynamic recrystallization occurs above 1450 °C in tungsten hot deformation process.
• Non-uniform microstructure of tungsten in hot deformation is mainly caused by grain growth.
• The stability hot deformation domain of tungsten was obtained.

Compression tests of multi-crystalline tungsten with Gleeble 3800 thermal simulator were performed in the temperature range of 1250–1550 °C and strain rate range of 0.001–1 s− 1. The flow stress-strain data of multi-crystalline tungsten were obtained. The processing map of the tungsten was established according to the theory of power dissipation and instability criterion. Together with the characterization of the microstructure, the flow instability domain and stability domain in hot deformation process of multi-crystalline tungsten were analyzed. The results of the tests and analysis showed that the dynamic recovery is the principal softening effect in the hot deformation process of multi-crystalline tungsten at elevated temperature. When the temperature reaches 1250 °C, a small amount of dynamic recrystallization occurs. It was found from the hot processing map that the stability deformation domain of multi-crystalline tungsten can be classified into four different situations in the strain range of 0.1–0.6. The temperature range and strain rate range corresponding to these four situations of stability deformation domain were given.

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