TY - JOUR
T1 - In Situ Analysis of the Phase Transformation Kinetics in the β-Water-Quenched Ti-5Al-5Mo-5V-3Cr-1Zr Alloy during Ageing after Fast Heating
AU - Paiotti Marcondes Guimaraes, Rafael
AU - Callegari, Bruna
AU - Warchomicka, Fernando Gustavo
AU - Aristizabal, Katherine
AU - Soldera, Flavio
AU - Mücklich, Frank
AU - Pinto, Haroldo Cavalcanti
PY - 2020/2/21
Y1 - 2020/2/21
N2 - Thermal treatments are the main route to achieve improvements in mechanical properties of β-metastable titanium alloys developed for structural applications in automotive and aerospace industries. Therefore, it is of vital importance to determine phase transformation kinetics and mechanisms of nucleation and precipitation during heat treatment of these alloys. In this context, the present paper focuses on the assessment of solid-state transformations in a β-water-quenched Ti-5Al-5Mo-5V-3Cr-1Zr alloy during the early stages of ageing treatment at 500 °C. In situ tracking of transformations was performed using high-energy synchrotron X-ray diffraction. The transformation sequence β + ω → α + α”iso + β is proposed to take place during this stage. Results show that isothermal α” phase precipitates from ω and from spinodal decomposition domains of the β phase, whereas α nucleates from ω, β and also from α” with different morphologies. Isothermal α” is considered to be the regulator of transformation kinetics. Hardness measurements confirm the presence of ω, although this phase was not detected by X-ray diffraction during the in situ treatment.
AB - Thermal treatments are the main route to achieve improvements in mechanical properties of β-metastable titanium alloys developed for structural applications in automotive and aerospace industries. Therefore, it is of vital importance to determine phase transformation kinetics and mechanisms of nucleation and precipitation during heat treatment of these alloys. In this context, the present paper focuses on the assessment of solid-state transformations in a β-water-quenched Ti-5Al-5Mo-5V-3Cr-1Zr alloy during the early stages of ageing treatment at 500 °C. In situ tracking of transformations was performed using high-energy synchrotron X-ray diffraction. The transformation sequence β + ω → α + α”iso + β is proposed to take place during this stage. Results show that isothermal α” phase precipitates from ω and from spinodal decomposition domains of the β phase, whereas α nucleates from ω, β and also from α” with different morphologies. Isothermal α” is considered to be the regulator of transformation kinetics. Hardness measurements confirm the presence of ω, although this phase was not detected by X-ray diffraction during the in situ treatment.
KW - high-energy X-ray diffraction
KW - near-beta titanium alloys
KW - ageing
KW - Rietveld refinement
KW - metastable phases
UR - https://doi.org/10.3390/qubs4010012
U2 - doi:10.3390/qubs4010012
DO - doi:10.3390/qubs4010012
M3 - Article
SN - 2412-382X
VL - 4
SP - 1
EP - 16
JO - Quantum Beam Science
JF - Quantum Beam Science
IS - 1
M1 - 12
ER -