Mechanical properties of tungsten nanowhiskers characterized by nanoindentation
(1. Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Physics and Information Science, Hunan Normal University, Changsha 410081, China;
3. School of Physics and Electronics, Central South University, Changsha 410083, China)
2. School of Physics and Information Science, Hunan Normal University, Changsha 410081, China;
3. School of Physics and Electronics, Central South University, Changsha 410083, China)
Abstract: The Mechanical properties of the hexagonal tungsten nanowhiskers, which were synthesized by chemical vapor deposition, were characterized by instrumented nanoindentation and atomic force microscope (AFM). The nanoindentation results show that tungsten nanowhiskers exhibit a hardness of (6.2±1.7) GPa and an elastic modulus of (225±20) GPa. According to the comparative test results, the tungsten nanowhiskers possess a comparable hardness to tungsten microwhiskers, and an hardness increase of 35% to the bulk single-crystal tungsten. The increase in the hardness of whiskers is attributed to the lacking of dislocation avalanche observed in the bulk single-crystal tungsten. The measured modulus is about 80% that of the tungsten microwhiskers, which can be contributed to the size effects of the nanowhiskers and the substrate effects in the nanoindentation test.
Key words: tungsten; nanowhiskers; mechanical properties; nanoindentation