Microstructure and mechanical properties of highly deformed Ti–6Al–4V

Gungor, M. N.; Üçok, I.; Kramer, Lawrence S.; Dong, Hao; Martin, Nicholas R.; Tack, W. T.

doi:10.1016/j.msea.2005.08.141

Cited by 27 publications

(27 citation statements)

References 2 publications

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“…While the grains in this study were larger than those reported in ASB microstructures of Ti-6Al-4V subjected to ballistic impact, [4][5][6][7][8][9][10] they still show a trend toward fine grains as the cutting surface is approached through the chip thickness. This trend toward finer grains corresponds to the variation in increasing strain and temperature as the cutting surface is approached.…”

Section: Discussionmentioning

confidence: 67%

“…[3] When subjected to high levels of strain at high strain rates, typical of ballistic impact conditions, Ti-6Al-4V is susceptible to shear localization and the formation of adiabatic shear bands (ASBs). [4][5][6][7][8] Various studies probed the microstructure within the 1-to 10-lm shear band widths and report fine grains of approximately 300-nm diameter. [4] In some cases, amorphous regions have also been reported in the ASBs of 304L and Fe-Ni-Cr alloys.…”

Section: Introductionmentioning

confidence: 99%

“…[9] Most reported studies on the ASB microstructure use specimens produced with various types of Kolsky or Hopkinson pressure bars to impart strain up to 0.5 at strain rates in the range of 10 3 to 10 4 s À1 . [5][6][7][8][9][10] A simpler experimental procedure using metal cutting is proposed to impart a wider range of higher shear strains (~1 to 10) at higher shear strain rates (up to 10 6 s À1 ) in a single pass of deformation. [12] Similar to conditions in pressure bar testing, adiabatic heating during the deformational process in metal cutting raises the temperature in the chips produced.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural Characterization of Ti-6Al-4V Metal Chips by Focused Ion Beam and Transmission Electron Microscopy

Schneider

Dong

Meyer

2011

Metall Mater Trans A

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During machining, the cutting surface of a metal is subjected to high strain rates and temperatures. Due to the small mass of the formed chip, the metal is rapidly quenched, preserving the as-machined microstructure. These extreme conditions are reported to be favorable to form nanograin or ultrafine-grain microstructures. However, detailed investigation of this region is problematic due to the size of the chips and the difficulty in preserving the cutting surface microstructure during traditional transmission electron microscopy (TEM) preparation. This study investigates the use of focused ion beam (FIB) specimen preparation to preserve and TEM to image the microstructure of the secondary deformation zone (SDZ) at the cutting surface in chips of Ti-6Al-4V formed during machining. Use of the FIB allowed precise extraction of a side or transverse view specimen, which preserved the cutting surface to reveal an inhomogeneous microstructure resulting from the nonuniform distribution of strain, strain rate, and temperature. Initial imaging of a conventional TEM foil prepared from the plan view of the cutting surface revealed microstructures ranging from heavily textured to regions of fine grains. Using FIB preparation of a transverse foil, a layered microstructure was observed revealing a variation of fine grains near the cutting surface, which transitioned to coarse grains toward the free surface. At the cutting surface, a 10-nm-thick recrystallized layer was observed capping a 20-nm-thick amorphous layer.

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Section: Discussionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructural Characterization of Ti-6Al-4V Metal Chips by Focused Ion Beam and Transmission Electron Microscopy

Schneider

Dong

Meyer

2011

Metall Mater Trans A

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“…In addition, the presence of platelets was not easily distinguishable from phase primarily due either to the relatively large volume percent of phase completely mixed in the matrix or to the fact that the extrusion deformation was accompanied by recrystallization and growth processes. 30) The extrusion process in this study was performed at temperatures slightly above the transus temperature ($1000 C) in which case the volume fraction of phase present in the matrix was reported to be up to 38% under standard heat treatment conditions, 33) though the actual microstructure can vary, depending on the exact extrusion and subsequent annealing temperatures. 24) According to previous investigations, 6,8) the fine W particle sizes (< $10 mm), as was used in this study, resulted in a larger amount of W dissolution in both Ti and Ti-6Al-4V matrices, as there indeed exists a theoretically complete solid solubility of W in Ti at elevated temperatures (Fig.…”

Section: Microstructurementioning

confidence: 99%

Influence of Processing on the Mechanical Properties of Ti-6Al-4V-Based Composites Reinforced with 7.5 mass% TiC and 7.5 mass% W

Choe

Abkowitz²,

Abkowitz³

2008

Mater. Trans.

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7.5 mass% TiC and 7.5 mass% W powder blends were densified with Ti-6Al-4V blends by combined cold and hot isostatic pressing (CHIP) method to result in three types of composites with differing processing histories, namely hot isostatic pressing (HIPping), extrusion, and casting, which were compared with their monolithic counterparts. Tensile and microhardness tests, along with compressive testing, were carried out to investigate the mechanical properties of powder metallurgy (P/M) Ti-6Al-4V-7.5%TiC-7.5%W composites at ambient temperature. Dissolution of W powder in the Ti-6Al-4V matrix during consolidation seems to be limited by the presence of TiC particles, which can in turn influence mechanical properties of the composites. Cast Ti-6Al-4V-7.5%TiC-7.5%W composite exhibits superior hardness, yield strength, and tensile strength, with a decrease in ductility, compared to its monolithic counterpart and other composites.

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“…The tensile ductility of α-β titanium alloys is mainly determined by two parameters, crack nucleation resistance and crack propagation resistance, and the former is the dominating parameter. Gungor et al pointed out that colony boundaries and α at prior β grain boundaries served as void nucleation sites [17]. Thus, the increasing volume of α p phases in the bimodal microstructure decreased the slip length and initiated more sites of void nucleation, leading to the higher ductility.…”

Section: Tensile Propertiesmentioning

confidence: 99%

Effect of Microstructure on Fracture Toughness and Fatigue Crack Growth Behavior of Ti17 Alloy

Rong

Wang³

et al. 2016

Metals

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Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) is used extensively in turbine engines, where fracture toughness and fatigue crack growth (FCG) resistance are important properties. However, most research on the alloy was mainly focused on deformation behavior and microstructural evolution, and there have been few studies to examine the effect of microstructure on the properties. Accordingly, the present work studied the influences of the microstructure types (bimodal and lamellar) on the mechanical properties of Ti17 alloy, including fracture toughness, FCG resistance and tensile property. In addition, the fracture modes associated with different microstructures were also analyzed via the observation of the fracture surface. The results found that the lamellar microstructure had a much higher fracture toughness and superior resistance to FCG. These results were discussed in terms of the tortuous crack path and the intrinsic microstructural contributions.

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Microstructure and mechanical properties of highly deformed Ti–6Al–4V

Cited by 27 publications

References 2 publications

Microstructural Characterization of Ti-6Al-4V Metal Chips by Focused Ion Beam and Transmission Electron Microscopy

Microstructural Characterization of Ti-6Al-4V Metal Chips by Focused Ion Beam and Transmission Electron Microscopy

Influence of Processing on the Mechanical Properties of Ti-6Al-4V-Based Composites Reinforced with 7.5 mass% TiC and 7.5 mass% W

Effect of Microstructure on Fracture Toughness and Fatigue Crack Growth Behavior of Ti17 Alloy

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