Effect of notches and microstructure on the fracture toughness of TiAl-based alloys

Pu, Zhongjie; Wu, Kuang‐Hsi; Shi, Jie; Zou, Dunxu

doi:10.1016/0921-5093(94)03217-3

Cited by 14 publications

(7 citation statements)

References 10 publications

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“…As per the finite element analysis by Nakamura et al, [40] for the specimen dimensions and the loading rates (K = 1 and c o = 6622 m/s) that are being used in the present investigation, the transition times are estimated by using Eq. [5] as t s~1 5 ls. The critical fracture Frame 12 is also marked on Fig.…”

Section: A Room-temperature Experiments: Dynamic Fracture Toughness mentioning

confidence: 98%

“…[39] Due to the brittle nature of this material, no fatigue precracking was performed; however, the notch was extended 1 mm beyond the V notch using an electrodischarge machining wire with a diameter of 0.006 in., to yield a notch radius of 75 lm. A detailed study was performed by Pu et al [5] to determine the effect of the notches and microstructure on the fracture toughness of Ti-46.5Al-2.5 V-1Cr (atomic percent). The fracture toughness was found to be independent of the notch radius up to a certain critical value, after which the fracture toughness increases linearly with the square root of the notch radius.…”

Section: Specimen Designmentioning

confidence: 99%

“…The results of these studies have provided information valuable in relating their dynamic fracture toughness to their chemical composition [1][2][3] and microstructural features. [2][3][4][5][6][7] In the recent past, the majority of the research on these alloys has focused on determining the quasistatic fracture toughness; the dynamic fracture of these alloys has been studied by relatively few researchers. Enoki and Kishi [8] investigated the effect of the loading rate on the fracture toughness in fully lamellar and duplex Ti-48Al (atomic percent) microstructures using a Charpy impact testing machine.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Fracture Initiation Toughness of a Gamma (Met-PX) Titanium Aluminide at Elevated Temperatures

Shazly

Prakash

Draper

2009

Metall Mater Trans A

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Recently, a new generation of titanium aluminide alloy named Gamma-Met PX (GKSS, Geesthacht, Germany) has been developed with better rolling and postrolling characteristics. Previous work on this alloy has shown the material to have higher strengths at room and elevated temperatures when compared with other gamma titanium aluminides. In particular, this new alloy has shown increased ductility at elevated temperatures under both quasistatic and high-strain-rate uniaxial compressive loading. However, its high-strain-rate tensile ductility at room and elevated temperatures is limited to~1 pct. In the present article, the results of a study investigating the effects of the loading rate and test temperature on the dynamic fracture initiation toughness in Gamma-Met PX are presented. A modified split Hopkinson pressure bar (MSHPB) was used along with high-speed photography, to determine the dynamic fracture initiation toughness. Three-point-bend fracture tests were conducted at impact speeds in the range 1 to 3.6 m/s and at test temperatures up to 1200°C. Furthermore, the effect of long-time high-temperature air exposure on the fracture toughness was investigated. The results show that the dynamic fracture initiation toughness decreases at test temperatures beyond 600°C. Moreover, the dynamic fracture initiation toughness was found to decrease with increasing exposure time. The reasons behind this drop are analyzed and discussed.

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Section: A Room-temperature Experiments: Dynamic Fracture Toughness mentioning

confidence: 98%

Section: Specimen Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Fracture Initiation Toughness of a Gamma (Met-PX) Titanium Aluminide at Elevated Temperatures

Shazly

Prakash

Draper

2009

Metall Mater Trans A

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“…In the literature, the dynamic fracture toughness has been found to be higher than the static fracture toughness in some materials, whereas in others, it is similar or even lower than the static fracture toughness [9][10][11][12][13][14]. Several investigators have also studied the effect of notch root radius on the static and dynamic fracture toughness in different materials [15][16][17][18][19][20][21][22][23][24]. These studies have shown that there exists a critical notch root radius below which the fracture toughness is independent of notch root radius and beyond which the fracture toughness increases linearly with square root of notch root radius.…”

Section: Introductionmentioning

confidence: 98%

Dynamic fracture toughness of a near alpha titanium alloy Timetal 834

Prasad¹,

Kamat²

2010

Journal of Alloys and Compounds

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“…Studies have indicated that the fracture toughness of TiAl-based alloys results from various factors including the microstructure types, lamellar orientation, colony size, interlamellar spacing, and internal stress. [18][19][20][21][22][23][24][25][26] The fully lamellar (FL) microstructure generally exhibits the highest fracture toughness among all the microstructure types. [18] The fracture resistance of the trans-lamellar mode is higher than that of the inter-lamellar mode.…”

Section: Introductionmentioning

confidence: 99%

Improved Fracture Toughness of Polycrystalline γ‐TiAl‐Based Intermetallic Alloys with a Favorable Deformation Mechanism of Twinning

et al. 2022

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High-density deformation nanotwins markedly strengthen TiAl-based alloys; however, the improvement in strength generally leads to a reduction in fracture toughness for most structural materials. It is, therefore, necessary to investigate the benefits of high-density deformation nanotwins for the improvement in fracture toughness of TiAl-based alloys. Herein, the fracture toughness of two Ti-45.5Al-4Cr-2.5Nb alloys with a favorable deformation mechanism of twinning (prepared by annealing the continuous casting (C. C.) alloy at 1250 C and 1270 C for different durations, respectively) is investigated and compared with that of the unannealed continuous casting (C. C.) alloy, in terms of room-temperature (RT) tensile properties and microstructures. It is found that the two heattreated Ti-45.5Al-4Cr-2.5Nb alloys exhibits a higher fracture toughness than the C. C. alloy. Shear ligaments and slip bands are the main toughening mechanisms for the two heat-treated alloys; their generation is closely related to the enhancement in the plastic deformability of lamellar structures. In addition, the increase in (B2 þ γ)-coupled structures is found to impose a negative effect on the toughening of the investigated alloys. High-density deformation nanotwins favor the improvement in fracture toughness of TiAl-based alloys by improving their fracture strength and plastic deformability, while decreasing their workhardening exponent.

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Effect of notches and microstructure on the fracture toughness of TiAl-based alloys

Cited by 14 publications

References 10 publications

Dynamic Fracture Initiation Toughness of a Gamma (Met-PX) Titanium Aluminide at Elevated Temperatures

Dynamic Fracture Initiation Toughness of a Gamma (Met-PX) Titanium Aluminide at Elevated Temperatures

Dynamic fracture toughness of a near alpha titanium alloy Timetal 834

Improved Fracture Toughness of Polycrystalline γ‐TiAl‐Based Intermetallic Alloys with a Favorable Deformation Mechanism of Twinning

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