Severe plastic deformation of amorphous alloys: I. Structure and mechanical properties

Transformation of Hume-Rothery phases under the action of high pressure torsion

“…In other words, the composition and structure of phases in a sample after severe plastic deformation can differ from those before deformation. In particular, the decomposition of supersaturated solid solutions [2,[5][6][7], the satura tion of the matrix with the second component (forma tion of solid solutions) [6,7], the formation of one or two different amorphous phases from crystalline phases [8][9][10], the decomposition of an amorphous phase with the formation of nanocrystals [11,12], and allotropic phase transformations (e.g., α-ε Co, α-γ Fe, α-β-ω Ti, or α-β-ω Zr) [2,4,[13][14][15][16] can occur. However, all listed phenomena were observed in phases with a relatively simple crystal lattice such as an fcc lattice with the space group Fm3m, a bcc lattice with the space group Im3m, and an hcp lattice with the space group P63.…”

The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

“…SPD also induces various phase transformations [12] such as formation [13][14][15] or decomposition [16][17][18][19][20] of supersaturated solid solution, dissolution of particles of a second solid phase [21][22][23][24][25][26], amorphization [27][28][29][30][31][32] and nanocrystallization [33][34][35]. Among this variety, very interesting are the phase transformations with formation of high-pressure phases.…”

Structure evolution of a zirconium-based amorphous alloy upon megaplastic strain in the bridgeman chamber

“…Our and above-described literature data suggest that conditions for the formation of nanoclusters of the crystal phase arise during strain in the Bridgeman chamber already on application of the compression. Typically, MPS in the Bridgeman chamber is structurally manifested through the formation of highly localized shear bands in which high stress level, local temperature increase, and high free volume concentration are observed [12]. It seems likely that nanoclusters that are in the region subjected to the action of the shear bands grow transforming into nanocrystals due to the increase of the temperature inside of them and of the free volume in the strained regions as well as due to the increased dynamic mobility of atoms.…”