Deformation and Fracture Behavior of TiAl in Compression Tests at Room Temperature

Nonaka, K.; Tanosaki, Kazuo; Fujita, Makoto; Chiba, Akihiko; Kawabata, Takeshi; Izumi, Osamu

doi:10.2320/matertrans1989.33.802

Cited by 7 publications

(3 citation statements)

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“…While in compression the samples showed yielding with an average yield strength of 1410MPa which is comparable to that of UFG -TiAl alloys with similar compositions and grain sizes [14] and significantly higher than that of coarse grained -TiAl alloys with similar compositions [13]. However Oehring et.…”

Section: Room Temperature Mechanical Behaviourmentioning

confidence: 95%

“…8(a) are caused by the easy separation of the powder particles at interparticle boundaries which are lack of bonding. It is expected that the original residual pores in the HIPed samples and the pores formed under high stress prior to fracture makes the UFG TiAl alloy sample have a lower ductility in compression than the coarse grained TiAl alloy with a similar composition [13]. In addition, the unreacted Ti regions found in the microstructure of the HIPed samples are also expected to adversely affect the room temperature mechanical properties (especially the ductility) due to their brittleness caused by the high total oxygen content of the HIPed sample.…”

Section: Room Temperature Mechanical Behaviourmentioning

confidence: 99%

“…Gerling et al have successfully manufactured Ti-45Al-5Nb-(0,0.5)C sheets by hot rolling of blocks produced by hot-isostatic pressing of pre-alloyed powder with corresponding composition [9]. A number of studies were focussed on either the tensile behaviour or the compressive behaviour of TiAl based alloys, showing interesting and valuable results [10][11][12][13]. However the studies on both tension and compression behaviours of same TiAl based alloys and their comparison are still scarce.…”

Section: Introductionmentioning

confidence: 99%

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The mechanical behaviour of an ultrafine grained Ti–47Al–2Cr (at%) alloy in tension and compression and at different temperatures

Nadakuduru

Zhang

Cao

et al. 2011

Materials Science and Engineering: A

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A c c e p t e d M a n u s c r i p t Research Highlights Powder metallurgy process has been used to produce UFG Ti-47Al-2Cr (at%) alloy. At room temperature, the UFG alloy was found to be ductile in compression (~ 4%). At elevated temperatures the alloy showed high tensile and compressive ductility. The yield strength at 900 o C is 55MPa in tension and ~ 33MPa in compression. *Research HighlightsPage 2 of 17 A c c e p t e d M a n u s c r i p t AbstractA bulk ultrafine grained (UFG) Ti-47Al-2Cr (at%) alloy has been produced using a powder metallurgy process that combines high energy mechanical milling (HEMM) of a mixture of Ti, Al and Cr powders to produce a Ti/Al/Cr composite powder and hot isostatic pressing (HIP) of the composite powder compact. The purpose of the present study is to determine the mechanical behaviour of the alloy in tension and compression at room temperature (RT) and elevated temperatures, and also to compare the compression behaviour of the material with its tensile behaviour. It has been found that due to the residual pores, lack of full level interparticle bonding and high oxygen content (0.87wt%) in the consolidated samples, the UFG TiAl based alloy has a very low room temperature tensile fracture strength of ~100MPa and shows no tensile ductility. However these microstructural defects and high oxygen content have much less significant effect on the room temperature compressive mechanical properties, and the alloy shows a high compressive yield strength of ~ 1410 MPa, and some ductility (plastic strain to fracture ~ 4%). At elevated temperatures of 800 o C and above, the alloy shows high tensile and compressive ductility as demonstrated by 75% tensile elongation to fracture and no cracking in upset forging with a height reduction of 50% at 900 o C. The yield strength of the alloy at 900 o C is 55MPa in tension and ~ 33MPa in compression, both of which are lower than those of coarse grained TiAl based alloys with similar compositions at 900 o C. This is due to a higher creep rate of the UFG alloy caused by the small grains. The good formability of the UFG TiAl based alloy as reflected by the lower critical temperature above which the alloy becomes highly formable indicates that the material can be used as a suitable precursor for secondary thermomechanical processing and super-plastic forming.

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Section: Room Temperature Mechanical Behaviourmentioning

confidence: 95%

Section: Room Temperature Mechanical Behaviourmentioning

confidence: 99%