Thermal stability of nanocrystalline Nb produced by severe plastic deformation

Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions

“…The Vickers hardness at the saturated level (HV) of a wide range of pure metals and semi-metals with various crystal structures processed through severe plastic deformation (SPD) have been reported [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]28,66]. In this work, we study the increment of hardness (∆HV) of 17 high purity (better than 99.9%) elements due to HPT reported in [4,5,9,10,23,28,66] (see Table 1).…”

“…Following extensive work in the field by a range of researchers, extensive data on the hardness and microstructure of HPT processed metals and alloys is now available (e.g. [4,5,6,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]). Data on hardness increase due to HPT have been published for over 20 pure metals, and several of the factors influencing the hardness of HPT processed pure metals have been investigated in some detail by Edelati and Horita [4,5].…”

Hardening mechanism of commercially pure Mg processed by high pressure torsion at room temperature

“…HPT processing significantly increases yield strength and hardness of nearly all metals and alloys. Microhardness of HPT processed metals are improved up to 100 % for pure Al [3,4], 130 % for pure Ti [5,6], 400 % for pure Fe [7] , 60 % for pure Cu [8], and also for a range of other metals strong hardening has been evidenced [9,10,11,12,13,14,15,16,17,18]. This is because the HPT process imposes a very large shear strain on the metal and a very large amount of dislocations and/or twins are generated in the metals, which further cause significant microstructure refinement.…”

Microstructures and Mechanical Properties of Pure V and Mo Processed by High-Pressure Torsion

“…Although many reports are available for Fe, [10][11][12][13] very limited applications have been reported on the bcc metals using the HPT process. [14][15][16][17][18][19] In this research, two bcc metals, V and Mo, are selected because not only there are few studies using the HPT process but also there is a marked difference in the strength between V and Mo where V is softer and lower melting point (2136 K) but Mo is harder and higher melting point (2883 K).…”