The dynamic spheroidisation behaviour of the lamellar Ti–22Al–25Nb alloy during hot compression at 970°C/0.01 s−1 and strain of 30%, 50% and 70% was investigated. The results showed the lamellar-O phase that participated in the B2 matrix could be obtained by hot pressed sintering from pre-alloy powders. The corresponding scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy observations indicated that the dynamic spheroidisation process can be divided into three stages, the first is the primary interphase high-energy defect stage, introduced by dislocation migration twinning and localised shearing. The second is the separation, and the last is the spheroidisation stages, which could be explained by boundary splitting and termination migration.
BanerjeeD, GogiaAK, NandyTK, A new ordered orthorhombic phase in a Ti3Al Nb alloy. Acta Metall. 1988;36:871–882. doi: 10.1016/0001-6160(88)90141-1
2.
EmuraS, TsuzakiK, TsuchiyaK.Improvement of room temperature ductility for Mo and Fe modified Ti2AlNb alloy. Mater Sci Eng A. 2010;528:355–362. doi: 10.1016/j.msea.2010.09.003
3.
MaoY, HagiwaraM, EmuraS.Creep behavior and tensile properties of Mo- and Fe-added orthorhombic Ti–22Al–11Nb–2Mo–1Fe alloy. Scr Mater. 2007;57:261–264. doi: 10.1016/j.scriptamat.2007.03.053
4.
BoehlertCJ, MajumdarBS.EetharamanV.Microstructure, creep, and tensile behavior of a Ti–21Al–29Nb(at.%) orthorhombic+B2 alloy. Intermetallics. 2006;14:412–422. doi: 10.1016/j.intermet.2005.08.006
5.
WangW, ZengWD, ChenX, Microstructural evolution, creep, and tensile behavior of a Ti–22Al–25Nb (at%) orthorhombic alloy. Mater Sci Eng A. 2014;603:176–184. doi: 10.1016/j.msea.2014.02.004
6.
ChenW, ChenZY, WuCC, The effect of annealing on microstructure and tensile properties of Ti–22Al–25Nb electron beam weld joint. Intermetallics. 2016;75:8–14. doi: 10.1016/j.intermet.2016.02.006
7.
DeySR, RoyS, SuwasS, Annealing response of the intermetallic alloy Ti–22Al–25Nb. Intermetallics. 2010;18:1122–1131. doi: 10.1016/j.intermet.2010.02.010
8.
JiaJB, ZhangKF, LiuLM, Hot deformation behavior and processing map of a powder metallurgy Ti–22Al–25Nb alloy. J Alloy Comp. 2014;600:215–221. doi: 10.1016/j.jallcom.2014.02.116
9.
NiuHZ, ChenYF, ZhangDL, Fabrication of a powder metallurgy Ti 2 AlNb-based alloy by spark plasma sintering and associated microstructure optimization. Mater Des. 2016;89:823–829. doi: 10.1016/j.matdes.2015.10.042
10.
LinP, HeZB, YuanSJ, Instability of the O-phase in Ti–22Al–25Nb alloy during elevated-temperature deformation. J Alloy Comp. 2013;578:96–102. doi: 10.1016/j.jallcom.2013.05.018
11.
EmuraS, AraokaA, HagiwaraM.B2 grain size refinement and its effect on room temperature tensile properties of a Ti–22Al–27Nb orthorhombic intermetallic alloy. Scr Mater. 2003;48:629–634. doi: 10.1016/S1359-6462(02)00462-1
12.
LütjeringG, WilliamsJC, GyslerA.Microstructure and mechanical properties of Materials. Singapore: World Scientific Publishing Co Pte Ltd.; 2000.
13.
ZhangSZ, ZhangCJ, DuZX, Microstructure and tensile properties of hot fogred high Nb containing TiAl based alloy with initial near lamellar microstructure. Mater Sci Eng A. 2015;642:16–21. doi: 10.1016/j.msea.2015.06.066
14.
XueC, ZengWD, WangW, Quantitative analysis on microstructure evolution and tensile property for the isothermally forged Ti2AlNb based alloy during heat treatment. Mater Sci Eng A. 2013;573:183–189. doi: 10.1016/j.msea.2013.03.003
15.
SemiatinSL, SeetharamanV, WeissI.Flow behavior and globularization kinetics during hot working of Ti–6Al–4V with a colony alpha microstructure. Mater Sci Eng A. 1999;263:257–271. doi: 10.1016/S0921-5093(98)01156-3
16.
SemiatinSL, ThomasJFJr., DadrasP.Processing-microstructure relationships for Ti-6Al-2Sn-4Zr-2Mo-0.1Si. Metall Trans A. 1983;14:2363–2374. doi: 10.1007/BF02663312
17.
WangKX, ZengWD, ZhaoYQ, Dynamic globularization kinetics during hot working of Ti-17 alloy with initial lamellar microstructure. Mater Sci Eng A. 2010;527:2559–2566. doi: 10.1016/j.msea.2010.01.034
18.
XuJW, ZengWD, JiaZQ, Static globularization kinetics for Ti-17 alloy with initial lamellar microstructure. J Alloy Comp. 2014;603:239–247. doi: 10.1016/j.jallcom.2014.03.082
19.
ZherebtsovS, MurzinovaM, SalishchevG, Spheroidization of the lamellar microstructure in Ti–6Al–4V alloy during warm deformation and annealing. Acta Mater. 2011;59:4138–4150. doi: 10.1016/j.actamat.2011.03.037
20.
MaX, ZengWD, XuB, Characterization of the hot deformation behavior of a Ti–22Al–25Nb alloy using processing maps based on the murty criterion. Intermetallics. 2012;20:1–7. doi: 10.1016/j.intermet.2011.08.027
21.
JiaJB, ZhangKF, LuZ.Dynamic globularization kinetics of a powder metallurgy Ti–22Al–25Nb alloy with initial lamellar microstructure during hot compression. J Alloy Comp. 2014;617:429–436. doi: 10.1016/j.jallcom.2014.08.034
22.
LiAB, HuangLJ, MengQY, Hot working of Ti–6Al–3Mo–2Zr–0.3Si alloy with lamellar α+β starting structure using processing map. Mater Des. 2009;30:1625–1631. doi: 10.1016/j.matdes.2008.07.031
23.
ZengWD, ShuY, ZhangXM, Hot workability and microstructure evolution of highly β stabilised Ti–25V–15Cr–0·3Si alloy. Mater Sci Tech. 2008;24:1222–1229. doi: 10.1179/174328407X185884
24.
MillerRM, BielerTR, SemiatinSL.Flow softening during hot working of Ti-6Al-4V with a lamellar colony microstructure. Scr Mater. 1999;40:1387–1393. doi: 10.1016/S1359-6462(99)00061-5
25.
DongXJ, LuSQ, ZhengHZ.Dynamic spheroidization kinetics behavior of Ti–6.5Al–2Zr–1Mo–1V alloy with lamellar microstructure. Trans Nonferrous Met Soc China. 2016;26:1301–1309. doi: 10.1016/S1003-6326(16)64233-4
26.
ZongYY, WenDS, LiuZY, Effect of hydrogen on the microstructural evolution of a γ-TiAl based alloy. Mater Lett2015;142:23–26. doi: 10.1016/j.matlet.2014.11.139
27.
BabuB, LindgrenLE.Dislocation density based model for plastic deformation and globularization of Ti-6Al-4V. Inter J Plasticity. 2013;50:94–108. doi: 10.1016/j.ijplas.2013.04.003
28.
LiL, LuoJ, YanJJ, Dynamic globularization and restoration mechanism of Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy during isothermal compression. J Alloy Comp. 2015;622:174–183. doi: 10.1016/j.jallcom.2014.10.043
29.
SongHW, ZhangSH, ChengMC.Dynamic globularization kinetics during hot working of a two phase titanium alloy with a colony alpha microstructure. J Alloy Comp. 2009;480:922–927. doi: 10.1016/j.jallcom.2009.02.059
30.
HeD, ZhuJC, LaiZH, An experimental study of deformation mechanism and microstructure evolution during hot deformation of Ti–6Al–2Zr–1Mo–1V alloy. Mater Des. 2013;46:38–48. doi: 10.1016/j.matdes.2012.09.045
31.
MullinsWW.Theory of thermal grooving. J Appl Phys. 1957;28:333–339. doi: 10.1063/1.1722742
