Study of alpha-case depth in Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V

Gaddam, Raghuveer; Sefer, Birhan; Pederson, Robert; Antti, Marta‐Lena

doi:10.1088/1757-899x/48/1/012002

Cited by 65 publications

(51 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, a comparison of Eqs. [33] and [3] indicates that the same critical strain is predicted at the cohesive strength when a ¼ 2b 1 . Thus, Eq.…”

Section: Discussionmentioning

confidence: 55%

“…[37] Both Eqs. [3] and [7] indicate that the critical strain at fracture decreases with increasing hydrogen content. The corresponding critical stress at fracture also decreases with increasing hydrogen contents, as illustrated in Figure 4.…”

Section: Hydrogen-induced Decohesion Modelmentioning

confidence: 99%

“…The dependence of the degradation of elastic modulus, critical cohesive stress, and critical cohesive strain on hydrogen content can be derived on the basis of Eqs. [1] and [3]. In particular, the relative elastic modulus reduction by hydrogen is given by…”

Section: Hydrogen-induced Decohesion During Cold Dwell Fatiguementioning

confidence: 99%

“…[2,3] There is also a desire to increase the strength of Ti alloys by controlling the texture in order to optimize the strength to match the in-service stresses. [4,5] Like Ni-based alloys, Ti-based alloys also exhibit cycle-dependent and time-dependent crack growth responses, which are often functions of temperature, [4,7] loading rate, and microstructural parameters such as grain size, phase morphology, [8,9] and crystallographic orientation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Hydrogen-Induced Decohesion Model for Treating Cold Dwell Fatigue in Titanium-Based Alloys

Chan

Moody

2016

Metall Mater Trans A

View full text Add to dashboard Cite

Cold dwell fatigue in near-alpha Ti alloys is a time-dependent fracture process at ambient temperature that involves fatigue in the presence of creep to produce cracking on low-energy fracture (e.g., cleavage) facets in hard alpha grains. In this article, cold dwell fatigue is treated as a hydrogen-induced decohesion process by using a nonlinear cohesive stress-strain relation to describe the decrease in the cohesive strength with increasing local hydrogen contents. It is postulated that during cold dwell fatigue, time-dependent deformation occurs by hai slip that results in dislocation pileups in soft alpha grains. The stress and dilatational fields of the dislocation pileups assist the transport of internal hydrogen atoms from soft grains to neighboring hard grains. The accumulation of internal hydrogen atoms at the trap sites leads to decohesion along crystallographic planes, which can be slip or hydride habit planes. The decohesion model is applied to treat cold dwell fatigue in Ti-6Al-4V with a basal-transverse texture by modeling the effects of hydrogen-induced decohesion on the stress-fatigue life (S-N f ) response, the time-dependent crack growth response (da/dt), and the fracture toughness (K c ) as functions of grain orientation. A probabilistic time-dependent fatigue crack growth analysis is then performed to assess the influence of microtexture on the dwell fatigue life of a Ti-6Al-4V ring disk subjected to a long-duration hold at the peak stress of the loading cycle. The results of the probabilistic life computations indicate that dwell fatigue resistance in Ti-6Al-4V may be improved and the risk of disk fracture may be reduced significantly by controlling the microtexture or reducing the size and volume fraction of hard alpha grains in the microstructure.

show abstract

“…In addition, a comparison of Eqs. [33] and [3] indicates that the same critical strain is predicted at the cohesive strength when a ¼ 2b 1 . Thus, Eq.…”

Section: Discussionmentioning

confidence: 55%

Section: Hydrogen-induced Decohesion Modelmentioning

confidence: 99%

Section: Hydrogen-induced Decohesion During Cold Dwell Fatiguementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Hydrogen-Induced Decohesion Model for Treating Cold Dwell Fatigue in Titanium-Based Alloys

Chan

Moody

2016

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…In order to evaluate the alpha-case layer, the polished cross-sections were etched using a standard etching procedure for titanium alloys, comprising two steps. More details about the etching procedure can be found elsewhere [15,16]. After etching the samples, the alpha-case layer was observed and measured using optical microscope Nikon Eclipse model MA200.…”

Section: Metallographic Preparation Of the Samples And Alpha-case Evamentioning

confidence: 99%

Evaluation of the Bulk and Alpha‐Case Layer Properties in Ti‐6Al‐4V at Micro‐And Nano‐Metric Length Scale

Sefer

Roa

Mateo

et al. 2016

Proceedings of the 13th World Conference on Titanium

View full text Add to dashboard Cite

In the present study the hardness of individual alpha ( )-Ti grains in Ti-6Al-4V was measured by nanoindentation using Berkovich tip indenter. Additionally, alpha-case layer was induced by performing isothermal heat treatment at 700 °C in air for 500 hours. The average hardness of the -Ti grains found in the bulk material and in the alpha-case layer were 6.7 ± 0.7 GPa and 9.4 ± 1.4 GPa, respectively. The high hardness of the -Ti grains in the alpha-case layer is due to solid solution strengthening caused by interstitial oxygen diffusion. The thickness of the developed alpha-case layer was estimated metallographically and compared with that measured from a hardness profile performed along the layer. Moreover, electron back-scattered diffraction was used to determine the local crystallographic orientation, the texture of the alloy microstructure, as well as phase fraction changes, where the nanoindentation measurements were performed.

show abstract

The Effect of Elevated Temperature Exposure on the Mechanical Properties of Ti834

Davies¹,

Thomas²,

Garratt³

et al. 2016

Proceedings of the 13th World Conference on Titanium

View full text Add to dashboard Cite

Study of alpha-case depth in Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V

Cited by 65 publications

References 11 publications

A Hydrogen-Induced Decohesion Model for Treating Cold Dwell Fatigue in Titanium-Based Alloys

A Hydrogen-Induced Decohesion Model for Treating Cold Dwell Fatigue in Titanium-Based Alloys

Evaluation of the Bulk and Alpha‐Case Layer Properties in Ti‐6Al‐4V at Micro‐And Nano‐Metric Length Scale

The Effect of Elevated Temperature Exposure on the Mechanical Properties of Ti834

Contact Info

Product

Resources

About