TY - JOUR
T1 - Severe plastic deformation induced precipitation of the ordered α2-Ti3Al phase in Ti–5Al–2Sn–2Zr–4Mo–4Cr
AU - Yang, C.
AU - Li, M. Q.
AU - Liu, Y. G.
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/15
Y1 - 2021/2/15
N2 - The typical two-phase titanium alloy of Ti–5Al–2Sn–2Zr–4Mo–4Cr was subjected to severe plastic deformation (SPD) by using high energy shot peening (HESP) at room temperature. Here, we experimentally investigated the SPD-induced atomic diffusion and phase transformation in the HESP processed Ti–5Al–2Sn–2Zr–4Mo–4Cr. The experimental results revealed that the ellipsoid-shaped precipitates with about 30–50 nm in thickness occurred in the surface layer of the HESP processed Ti–5Al–2Sn–2Zr–4Mo–4Cr, which was characterized to be the ordered α2-Ti3Al phase with the D019 crystal structure. The underlying formation mechanism of these ordered α2-Ti3Al precipitates was attributed to the SPD-induced atomic diffusion behaviors at room temperature, i.e., SPD-induced diffusive phase transformation, significantly different from the conventional ordering transformation driven by thermodynamics at high temperature. During HESP, the extremely high stress and strain level provided the potential conditions for precipitation of α2-Ti3Al phase; meanwhile, the generation of high-density dislocations accelerated the atomic diffusion, thereby promoting the nucleation of α2-Ti3Al phase. Furthermore, the significant reduction of grain size to nanometer contributed to the stability of α2-Ti3Al phase at room temperature.
AB - The typical two-phase titanium alloy of Ti–5Al–2Sn–2Zr–4Mo–4Cr was subjected to severe plastic deformation (SPD) by using high energy shot peening (HESP) at room temperature. Here, we experimentally investigated the SPD-induced atomic diffusion and phase transformation in the HESP processed Ti–5Al–2Sn–2Zr–4Mo–4Cr. The experimental results revealed that the ellipsoid-shaped precipitates with about 30–50 nm in thickness occurred in the surface layer of the HESP processed Ti–5Al–2Sn–2Zr–4Mo–4Cr, which was characterized to be the ordered α2-Ti3Al phase with the D019 crystal structure. The underlying formation mechanism of these ordered α2-Ti3Al precipitates was attributed to the SPD-induced atomic diffusion behaviors at room temperature, i.e., SPD-induced diffusive phase transformation, significantly different from the conventional ordering transformation driven by thermodynamics at high temperature. During HESP, the extremely high stress and strain level provided the potential conditions for precipitation of α2-Ti3Al phase; meanwhile, the generation of high-density dislocations accelerated the atomic diffusion, thereby promoting the nucleation of α2-Ti3Al phase. Furthermore, the significant reduction of grain size to nanometer contributed to the stability of α2-Ti3Al phase at room temperature.
KW - Diffusive phase transformation
KW - High energy shot peening
KW - Precipitates
KW - Severe plastic deformation
KW - α-TiAl phase
UR - http://www.scopus.com/inward/record.url?scp=85091601932&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2020.157277
DO - 10.1016/j.jallcom.2020.157277
M3 - 文章
AN - SCOPUS:85091601932
SN - 0925-8388
VL - 854
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
M1 - 157277
ER -