Enhanced hot-hardness in nanograined Nb with stable grain boundary at small grain size
Abstract
Nanograined pure Nb samples with two types of grain sizes (15 nm and 59 nm) were prepared by high-pressure torsion. The 15-nm-grained sample has a higher fraction of low-angle grain boundaries and CSL boundaries compared with the 59-nm-grained sample. These structures significantly reduce the grain boundary energy and suppress the grain coarsening rate under thermomechanical conditions, endowing the 15-nm-grained sample with an ultra-high hot-hardness of 6.3 GPa at 800 °C, which is threefold higher than that of the 59-nm-grained specimen. This provides a novel strategy for designing high-performance heat-resistant BCC refractory metals with stable grain boundaries at small grain sizes.
Fields of Study & Subjects
Microstructure and mechanical properties
Surface Treatment and Residual Stress
Metal and Thin Film Mechanics
Publication details
- Journal / source
- Materials Research Letters
- Publisher
- Informa UK Limited
- Volume
- 14
- Issue
- 4
- Pages
- 477–484
- Publication date
- 18 February 2026
- Language
- EN