Skip to main content Accessibility help

Effect of growth rate on microstructures and microhardness in directionally solidified Ti–47Al–1.0W–0.5Si alloy

  • Tong Liu (a1), Liangshun Luo (a1), Yanqing Su (a1), Liang Wang (a1), Xinzhong Li (a1), Ruirun Chen (a1), Jingjie Guo (a1) and Hengzhi Fu (a1)...


Ti–47Al–1.0W–0.5Si (at.%) alloy was directionally solidified in the range of growth rate (V) (V = 3–100 μm/s) at a constant temperature gradient (G = 18 K/mm). It was found that α phase was the primary phase of the alloy. Both primary dendritic arm spacing (λ) and interlamellar spacing (λs) decreased with increase of the growth rate (V) according to the relationship of λ ∝ V −0.356 and λsV −0.49, respectively. The Solidification segregation occurred since the enrichment of the solute element W in primary α phase during solidification. The degree of the segregation increased with the increase of the growth rate (V). The results also revealed that the lamellar orientation was not always perpendicular to the growth direction (GD) because the GD of primary α dendritic deviated from the preferred $\left\langle {0001} \right\rangle$ direction. The microhardness increased with increasing growth rate (V) according to H V ∝ 289.5V 0.12 because of the microstructure refinement.


Corresponding author

a) Address all correspondence to these authors. e-mail:
b) e-mail:


Hide All
1. Kim, S., Hong, J.K., Na, Y., Yeom, J., and Kim, S.E.: Development of TiAl alloys with excellent mechanical properties and oxidation resistance. Mater. Des. 54, 814819 (2014).
2. Clemens, H. and Mayer, S.: Design, processing, microstructure, properties, and applications of advanced intermetallic TiAl alloys. Adv. Eng. Mater. 15, 191215 (2013).
3. Johnson, D.R., Inui, H., Muto, S., Omiya, Y., and Yamanaka, T.: Microstructural development during directional solidification of α-seeded TiAl alloys. Acta Mater. 54, 10771085 (2006).
4. Inui, H., Oh, M.H., Nakamura, A., Yamaguchi, M.: Room-temperature tensile deformation of polysynthetically twinned (PST) crystals of TiAl. Acta Mater. 40, 30953140 (1992).
5. Johnson, D.R., Inui, H. and Yamaguch, M.: Directional solidification and microstructural control of the TiAl/Ti3Al lamellar microstructure in TiAl-Si alloys. Acta Mater. 44, 25232535 (1996).
6. Johnson, D.R., Masuda, Y., Inui, H., Yamaguchi, M.: Alignment of the TiAl/Ti3Al lamellar microstructure in TiAl alloys by growth from a seed material. Acta Mater. 45, 25232533 (1997).
7. Kim, S.E., Lee, Y.T., Oh, M.H., Inui, H., and Yamaguchi, M.: Directional solidification of TiAl base alloys using a polycrystalline seed. Mater. Sci. Eng., A 329, 2530 (2002).
8. Lee, H.N., Johnson, D.R., Inui, H., Oh, M.H., Wee, D.M., and Yamaguchi, M.: A composition window in the TiAl–Mo–Si system suitable for lamellar structure control through seeding and directional solidification. Mater. Sci. Eng., A 329, 1924 (2002).
9. Jung, I.S., Jang, H.S., Oh, M.H., Lee, J.H., and Wee, D.M.: Microstructure control of TiAl alloys containing β stabilizers by directional solidification. Mater. Sci. Eng., A 329–331, 1318 (2002).
10. Jung, I., Oh, M., Park, N., Kumar, K.S., and Wee, D.: Lamellar boundary alignment of DS-processed TiAl–W alloys by a solidification procedure. Met. Mater. Int. 13, 455 (2007).
11. Dong, S., Chen, R., Guo, J., Ding, H., Su, Y., and Fu, H.: Effect of heat treatment on microstructure and mechanical properties of cast and directionally solidified high-Nb contained TiAl-based alloys. J. Mater. Res. 30, 112 (2015).
12. Lapin, J., Ondrú, L., and Nazmy, M.: Directional solidification of intermetallic Ti–46Al–2W–0.5Si alloy in alumina moulds. Intermetallics 10, 10191031 (2002).
13. Kenel, C. and Leinenbach, C.: Influence of Nb and Mo on microstructure formation of rapidly solidified ternary Ti–Al–(Nb, Mo) alloys. Intermetallics 69, 8289 (2016).
14. Hu, D.: Role of boron in TiAl alloy development: A review. Rare Met. 35, 114 (2015).
15. Imayev, R.M., Imayev, V.M., Oehring, M., and Appel, F.: Alloy design concepts for refined gamma titanium aluminide based alloys. Intermetallics 15, 451460 (2007).
16. Brotzu, A., Felli, F., and Pilone, D.: Effect of alloying elements on the behaviour of TiAl-based alloys. Intermetallics 54, 176180 (2014).
17. Yin, W.M., Lupinc, V., and Battezzati, L.: Microstructure study of a γ-TiAl based alloy containing W and Si. Mater. Sci. Eng., A 239–240, 713721 (1997).
18. Hodge, A.M., Hsiung, L.M., and Nieh, T.G.: Creep of nearly lamellar TiAl alloy containing W. Scr. Mater. 51, 411415 (2004).
19. Yu, R., He, L.L., Jin, Z.X., Guo, J.T., Ye, H.Q., and Lupinc, V.: On the orientation relationship between Ti5Si3 precipitates and B2 phase in a Ti–47Al–2W–0.5Si alloy. Scr. Mater. 44, 911916 (2001).
20. Fan, J., Li, X., Su, Y., Chen, R., Guo, J., and Fu, H.: Dependency of microstructure parameters and microhardness on the temperature gradient for directionally solidified Ti–49Al alloy. Mater. Chem. Phys. 130, 12321238 (2011).
21. Fan, J., Li, X., Su, Y., Guo, J., and Fu, H.: The microstructure parameters and microhardness of directionally solidified Ti–43Al–3Si alloy. J. Alloys Compd. 506, 593599 (2010).
22. Kaya, H., Çadırlı, E., and Gündüz, M.: Directional cellular growth of Al-2 wt% Li bulk samples. Appl. Phys. A 94, 155165 (2009).
23. Kaya, H., Gündüz, M., Çadırlı, E., and Maraşlı, N.: Dependency of microindentation hardness on solidification processing parameters and cellular spacing in the directionally solidified Al based alloys. J. Alloys Compd. 478, 281286 (2009).
24. Böyük, U. and Maraşlı, N.: The microstructure parameters and microhardness of directionally solidified Sn–Ag–Cu eutectic alloy. J. Alloys Compd. 485, 264269 (2009).
25. Çadırlı, E., Kaya, H., and Gündüz, M.: Effect of growth rates and temperature gradients on the lamellar spacing and the undercooling in the directionally solidified Pb–Cd eutectic alloy. Mater. Res. Bull. 38, 14571476 (2003).
26. Böyük, U., Maraşlı, N., Kaya, H., Çadırlı, E., and Keşlioğlu, K.: Directional solidification of Al–Cu–Ag alloy. Appl. Phys. A: Mater. Sci. Process. 95, 923932 (2009).
27. Zhong, H., Li, S., Kou, H., and Li, J.: The solidification path related columnar-to-equiaxed transition in Ti–Al alloys. Intermetallics 59, 8186 (2015).
28. Yamaguchia, M., Johnson, D.R., Lee, H.N., and Inui, H.: Directional solidification of TiAl-base alloys. Intermetallics 8, 511517 (2000).
29. Lapin, J. and Gabalcová, Z.: Solidification behaviour of TiAl-based alloys studied by directional solidification technique. Intermetallics 19, 797804 (2011).
30. Fan, J., Li, X., Su, Y., Guo, J., and Fu, H.: Effect of growth rate on microstructure parameters and microhardness in directionally solidified Ti–49Al alloy. Mater. Des. 34, 552558 (2012).
31. Ding, X.F., Lin, J.P., Qi, H., Zhang, L.Q., Song, X.P., and Chen, G.L.: Microstructure evolution of directionally solidified Ti–45Al–8.5Nb–(W, B, Y) alloys. J. Alloys Compd. 509, 40414046 (2011).
32. Chen, G.L., Xu, X.J., Teng, Z.K., Wang, Y.L., and Lin, J.P.: Microsegregation in high Nb containing TiAl alloy ingots beyond laboratory scale. Intermetallics 15, 625631 (2007).
33. Fan, J., Li, X., Su, Y., Chen, R., Guo, J., and Fu, H.: Directional solidification of Ti–49 at.%Al alloy. Appl. Phys. A: Mater. Sci. Process. 105, 239248 (2011).
34. Kim, M.C., Oh, M.H., Lee, J.H., Inui, H., Yamaguchi, M., and Wee, D.M.: Composition and growth rate effects in directionally solidified TiAl alloys. Mater. Sci. Eng., A 239, 570576 (1997).
35. Haxhimali, T., Karma, A., Gonzales, F., and Rappaz, M.: Orientation selection in dendritic evolution. Nat. Mater. 5, 660664 (2006).
36. Lapin, J.: Effect of lamellar structure on microhardness and yield stress of directionally solidified intermetallic Ti–46Al–2W–0.5Si alloy. J. Mater. Sci. Lett. 22, 747749 (2003).



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed