材料科学与技术 ›› 2020, Vol. 39 ›› Issue (0): 56-73.DOI: 10.1016/j.jmst.2019.07.052
收稿日期:
2019-06-11
修回日期:
2019-07-13
接受日期:
2019-07-28
出版日期:
2020-02-15
发布日期:
2020-03-11
Pengfei Gaoab*(), Mingwang Fub, Mei Zhana*(
), Zhenni Leia, Yanxi Lia
Received:
2019-06-11
Revised:
2019-07-13
Accepted:
2019-07-28
Online:
2020-02-15
Published:
2020-03-11
Contact:
Gao Pengfei,Zhan Mei
. [J]. 材料科学与技术, 2020, 39(0): 56-73.
Pengfei Gao, Mingwang Fu, Mei Zhan, Zhenni Lei, Yanxi Li. Deformation behavior and microstructure evolution of titanium alloys with lamellar microstructure in hot working process: A review[J]. J. Mater. Sci. Technol., 2020, 39(0): 56-73.
Fig. 1. The typical lamellar microstructure after primary hot working in β-phase region (The microstructure of TA15 alloy after heating to 1020 ℃, hold 5 min then air cooled).
Misorientation types | Rotation axis/angle | Prandom (%) |
---|---|---|
A | I (identity) | 8.3 |
B | [1 1 2¯ 0]/60° | 16.6 |
C | [10 7¯ 17 3]/60.83° | 33.3 |
D | [ | 16.6 |
E | [ | 16.6 |
F | [ | 8.3 |
Table 1 Misorientations between α variants (expressed in axis/angle pairs) inherited from the same parent β grain and the corresponding probabilities without variant selection [21].
Misorientation types | Rotation axis/angle | Prandom (%) |
---|---|---|
A | I (identity) | 8.3 |
B | [1 1 2¯ 0]/60° | 16.6 |
C | [10 7¯ 17 3]/60.83° | 33.3 |
D | [ | 16.6 |
E | [ | 16.6 |
F | [ | 8.3 |
Fig. 6. The typical evolution of lamellar α during hot deformation of Ti-6Al-4 V alloy with lamellar microstructure at 600 ℃ and 0.001 s-1: (a) prior to deformation, and after height reductions of (b) 25%, (c) 50% and (d) 70% [11].
Fig. 7. Orientation distribution of lamellar α traces relative to the compression axis for Ti-6Al-4 V with lamellar microstructure deformed at 900 ℃, 0.1 s-1 to different strains [12].
Fig. 8. The typical crystallographic texture evolution of lamellar α during hot deformation of Ti-6Al-4 V alloy with lamellar microstructure at 950 ℃ and 0.1 s-1: (a) ε = 0, (b) ε = 0.2, (c) ε = 0.7, (d) ε = 1.0 [42].
Fig. 9. The kinking of lamellar colonies during hot compression (a) and tension (b) of Ti-6Al-4 V at 900 ℃, 0.1 s-1. The compression/tension axis is vertical in both micrographs. [46].
Fig. 10. The SEM image (a) and corresponding inverse pole figure (b) of a region containing kinking of lamellar α in the hot deformation of TA15 alloy with lamellar microstructure [17]. (In the inverse pole figure, β phase is indicated by gray areas, the black lines correspond to HABs, and the silver lines represent LABs).
Fig. 13. The semi-quantitative relationship between globularization efficiency and c-axis tilt from compression direction (Taylor factor) of lamellar α [45].
Fig. 15. Schematic representation of two-stage compression with parallel (Sample P) or vertical (Sample V) directions in the second compression stage and the corresponding results of globularization kinetics [68].
Fig. 17. Shear band and flow localization in the hot working of titanium alloy with lamellar microstructure: (a) Ti17 alloy deformed at 780 ℃, 10 s-1 and 30% [71]; (b) Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy deformed at 770 ℃, 5 s-1 and 60% [72]; (c) Ti-6Al-4 V alloy deformed at 850 ℃, 10 s-1 and 50% [73].
Temperature (℃) | Strain rate (s-1) | Δσ/σp at ε¯=0.50 | ||
---|---|---|---|---|
Heating related softening | Microstructure related softening | Total softening | ||
815 | 10-3 | 0.00 | 0.26 | 0.26 |
815 | 10-1 | 0.09 | 0.29 | 0.38 |
815 | 101 | 0.16 | 0.12 | 0.28 |
900 | 10-3 | 0.00 | 0.23 | 0.23 |
900 | 10-1 | 0.09 | 0.31 | 0.40 |
900 | 101 | 0.15 | 0.13 | 0.28 |
955 | 10-3 | 0.00 | 0.16 | 0.16 |
955 | 10-1 | 0.10 | 0.23 | 0.33 |
955 | 101 | 0.17 | 0.05 | 0.22 |
Table 2 Comparisons between the softening extents related to deformation heating and microstructure changes at different conditions for a Ti-6Al-4 V alloy with lamellar microstructure [12].
Temperature (℃) | Strain rate (s-1) | Δσ/σp at ε¯=0.50 | ||
---|---|---|---|---|
Heating related softening | Microstructure related softening | Total softening | ||
815 | 10-3 | 0.00 | 0.26 | 0.26 |
815 | 10-1 | 0.09 | 0.29 | 0.38 |
815 | 101 | 0.16 | 0.12 | 0.28 |
900 | 10-3 | 0.00 | 0.23 | 0.23 |
900 | 10-1 | 0.09 | 0.31 | 0.40 |
900 | 101 | 0.15 | 0.13 | 0.28 |
955 | 10-3 | 0.00 | 0.16 | 0.16 |
955 | 10-1 | 0.10 | 0.23 | 0.33 |
955 | 101 | 0.17 | 0.05 | 0.22 |
Fig. 19. The dislocation substructure and subgrain structure (LAB) within the lamellar α and β phases: (a) Ti-6Al-4 V alloy deformed at 600 ℃ to 25% height reduction (LAB is depicted as red line) [11]; (b) Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy deformed at 800 ℃ to the strain of 0.11 (LAB is depicted as yellow line) [82];(c) Ti-6Al-4 V alloy deformed at 800 ℃ to the strain of 0.29 [83].
Temperature(℃) | ks(MPam)at$\dot{\varepsilon}$(s-1)= | ks'MPamat$\dot{\varepsilon}$s-1= | ||||
---|---|---|---|---|---|---|
0.1 | 1.0 | 10.0 | 0.1 | 1.0 | 10.0 | |
Based on σp v.s. l-1/2 | Based on (σp-σss) v.s. l-1/2 | |||||
815 | 0.0296 | 0.0526 | 0.0547 | 0.0286 | 0.0518 | 0.0537 |
900 | 0.0242 | 0.0322 | 0.0424 | 0.0193 | 0.0283 | 0.0442 |
Table 3 The Hall-Petch constants based on σp v.s. l-1/2 and (σp-σss) vs. l-1/2 at different conditions [39].
Temperature(℃) | ks(MPam)at$\dot{\varepsilon}$(s-1)= | ks'MPamat$\dot{\varepsilon}$s-1= | ||||
---|---|---|---|---|---|---|
0.1 | 1.0 | 10.0 | 0.1 | 1.0 | 10.0 | |
Based on σp v.s. l-1/2 | Based on (σp-σss) v.s. l-1/2 | |||||
815 | 0.0296 | 0.0526 | 0.0547 | 0.0286 | 0.0518 | 0.0537 |
900 | 0.0242 | 0.0322 | 0.0424 | 0.0193 | 0.0283 | 0.0442 |
Fig. 25. Bright field micrographs of Ti-5-5-5-3 deformed at 785 ℃ to strain of 0.1: (a) regions of high disloaction density in lamellar α, (b) slip transmission across α/β interfaces.
Flow softening source | Main influencing factors | General influencing laws on flow softening |
---|---|---|
Deformation heating | •Temperature •Strain rate | Lower temperature and higher strain rate promote the deformation heating and flow softening |
Evolution of dislocation substructure and dynamic recovery (DRV) | Higher temperature and lower strain rate facilitate the evolution of dislocation substructure, DRV and flow softening | |
Dynamic globularization of lamellar α | -- | -- |
Kinking of lamellar α | •Temperature •Strain rate | Lower temperature and higher strain rate promote lamellar α kinking and flow softening |
Evolution of mechanical texture and crystallographic texture | •Mechanical texture and crystallographic texture of the initial microstructure •Compression direction | -- |
Loss of Hall-Petch strengthening associated with α/β interfaces | •Temperature •Strain rate •Lamellar α thickness | Lower temperature, higher strain rate and smaller lamellar α thickness are beneficial to the Hall-Petch strengthening loss and flow softening |
Adiabatic shear band and flow localization | •Temperature •Strain rate | Lower temperature and higher strain rate would increase the tendency to produce adiabatic shear band, flow localization and flow softening |
Table 4 Main influencing factors and laws for the flow softening of lamellar microstructure during hot deformation.
Flow softening source | Main influencing factors | General influencing laws on flow softening |
---|---|---|
Deformation heating | •Temperature •Strain rate | Lower temperature and higher strain rate promote the deformation heating and flow softening |
Evolution of dislocation substructure and dynamic recovery (DRV) | Higher temperature and lower strain rate facilitate the evolution of dislocation substructure, DRV and flow softening | |
Dynamic globularization of lamellar α | -- | -- |
Kinking of lamellar α | •Temperature •Strain rate | Lower temperature and higher strain rate promote lamellar α kinking and flow softening |
Evolution of mechanical texture and crystallographic texture | •Mechanical texture and crystallographic texture of the initial microstructure •Compression direction | -- |
Loss of Hall-Petch strengthening associated with α/β interfaces | •Temperature •Strain rate •Lamellar α thickness | Lower temperature, higher strain rate and smaller lamellar α thickness are beneficial to the Hall-Petch strengthening loss and flow softening |
Adiabatic shear band and flow localization | •Temperature •Strain rate | Lower temperature and higher strain rate would increase the tendency to produce adiabatic shear band, flow localization and flow softening |
Fig. 26. The comparison of globularization fraction of Ti-17 sample deformed to 45% reduction at 840 ℃ between experimental and predicted results by integrated model [90]. (‘E’ and ‘S’ represent experiment data and simulation results, respectively).
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