Influence of HPT Deformation Temperature on Microstructures and Thermal Stability of Ultrafine-Grained Tungsten

Abstract:

In the present work high pressure torsion (HPT) was imposed on commercial purity (CP) tungsten at different temperatures of 450 °С and 490 °С to achieve different microstructures and grain boundary misorientation spectra (GBMS). After HPT at 450°С, ultrafine grained microstructure with an average grain size of ~150 nm was developed in the metal. HPT at 490 °С results in an elongated structures with average width of ~500nm. EBSD investigations showed that over 92% are HAGB type in microstructure HPT-processed at 450°С, and in contrast, over 50% of grain boundaries are LAGB in sample processed at 490°С. Annealing at 900°С for 1h, of the sample with homogeneous UFG structure resulted from HPT at 450°C, leads to only limited decrease (~20%) in microhardness.

• Periodical: Materials Science Forum (Volumes 584-586)
• Pages: 1000-1005
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.584-586.1000
• Online since: June 2008
• Authors: Yue Zhang, Artur V. Ganeev, X. Gao, Alfred V. Sharafutdinov, Jing Tao Wang, Igor V. Alexandrov
• Keywords: Deformation Temperature, High-Angle Grain Boundary (HAGB), Low-Angle Grain Boundary (LAGB), Thermal Stability, Ultrafine Grained Structure

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