Abstract
An ultrafine grained (UFG) Ti–47Al–2Cr (at.%) alloy has been synthesized using a combination of high energy mechanical milling and hot isostatic pressing (HIP) of a Ti/Al/Cr composite powder compact. The material produced has been tensile tested at room temperature, 700 and 800 °C, respectively, and the microstructure of the as-HIPed material and the microstructure and fracture surfaces of the tensile tested specimens have been examined using X-ray diffractometry, optical microscopy, scanning electron microscopy and transmission electron microscopy. The alloy shows no ductility during tensile testing at room temperature and 700 °C, respectively, but very high ductility (elongation to fracture 70–100%) when tensile tested 800 °C, indicating that its brittle to ductile transition temperature (BDTT) falls within the temperature range of 700–800 °C. The retaining of ultrafine fine equiaxed grain morphology after the large amount of plastic deformation of the specimens tensile tested at 800 °C and the clear morphology of individual grains in the fractured surface indicate that grain boundary sliding is the predominant deformation mechanism of plastic deformation of the UFG TiAl based alloy at 800 °C. Cavitation occurs at locations fairly uniformly distributed throughout the gauge length sections of the specimens tensile tested at 800 °C, again supporting the postulation that grain boundary sliding is the dominant mechanism of the plastic deformation of the UFG TiAl alloys at temperatures above their BDTT. The high ductility of the UFG alloy at 800 °C and its fairly low BDTT indicates that the material a highly favourable precursor for secondary thermomechanical processing.
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References
Djanarthany S, Viala JC, Bouix J (2001) Mater Chem Phys 72:301
Morris MA, Leboeuf M (1997) Mater Sci Eng A 239:429
Imayev R, Shagiev M, Salishchev G, Imayev V, Valitov V (1996) Scripta Mater 34:985
Imavey VM, Salishchev GA, Shagiev MR, Kuznetsov AV, Imavey RM, Senkov ON, Froes FH (2001) Mater Sci Eng A 300:263
Haanappel VAC, Clemens H, Stroosnijder MF (2002) Intermetallics 10:293
Rishel LL, Biery NE, Raban R, Gandelsman VZ, Pollock TM, Cramb AW (1998) Intermetallics 6:629
Gerling R, Clemens H, Schimansky FP (2004) Adv Eng Mater 6:23
Hsiung LM, Nieh TG (2004) Mater Sci Eng A 364:1
Wegmann G, Gerling R, Schimansky FP, Clemens H, Bartels A (2002) Intermetallics 10:511
Shagiev MR, Senkov ON, Salishchev GA, Froes FH (2000) J Alloy Compd 313:201
Yang SH, Kim MS, Kim WY, Chiba A (2003) J Metastab Nanocryst Mater 15–16:373
Maziasz PJ, Liu CT (1998) Metall Mater Trans A 29:105
Thomas M, Raviart JL, Popoff F (2005) Intermetallics 13:944
Yu HB, Zhang DL, Chen YY, Cao P, Gabbitas B (2009) J Alloy Compd 474:105
Chen YY, Yu HB, Zhang DL, Chai LH (2009) Mater Sci Eng A 525:166
Bohn R, Klassen T, Bormann R (2001) Intermetallics 9:559
Liu CT, Schneibe JH, Maziasz PJ, Wright JL, Easton DS (1996) Intermetallics 4:429
Kim YW (1995) Mater Sci Eng A 192/193:519
Wu Y, Li XW, Zhou SX, Hwang SK (2007) J Iron Steel Res Int 14:104
Dimiduck DM (1999) Mater Sci Eng A 263:281
Gerling R, Schimansky FP, Clemens H (2003) Wear 249:566
Wang GX, Dahms M (1993) J Mater Perform 45:52
Beddoes J, Zhao L, Au P, Wallace W (1995) Mater Sci Eng A 192/193:324
Clemens H, Glatz W, Appel F (1996) Scr Mater 35:429
Shagiev MR, Senkov ON, Salishchev GA, Froes FH (2000) J Alloy Compd 313:201
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The authors would like to thank the Foundation for Research, Science, and Technology (FRST), New Zealand for the financial support to the research work presented in this paper.
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Nadakuduru, V.N., Zhang, D.L., Gabbitas, B. et al. Tensile properties and fracture behaviour of an ultrafine grained Ti–47Al–2Cr (at.%) alloy at room and elevated temperatures. J Mater Sci 47, 1223–1233 (2012). https://doi.org/10.1007/s10853-011-5887-8
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DOI: https://doi.org/10.1007/s10853-011-5887-8