Microstructure stability and damage mechanisms in an α/β Ti-6Al-4V-0.55Fe alloy during low cycle dwell-fatigue at room temperature

2021 ◽  
pp. 106585
Author(s):  
Shan Shi ◽  
Qinghua Deng ◽  
Hang Zhang ◽  
Liang Feng ◽  
Xiangjun Xu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Damage Mechanisms ◽  
Microstructure Stability ◽  
Dwell Fatigue

On the damage mechanisms during compressive dwell-fatigue of β-annealed Ti-6242S alloy

2021 ◽  
Vol 146 ◽  
pp. 106158
Author(s):  
M. Rezaei ◽  
A. Zarei-Hanzaki ◽  
A.S. Anousheh ◽  
H.R. Abedi ◽  
F. Pahlevani ◽  
...  
Keyword(s):  
Damage Mechanisms ◽  
Dwell Fatigue

scholarly journals The rupture life prediction in cold dwell fatigue of Ti-6Al-4V based on the creep deformation

2020 ◽  
Vol 321 ◽  
pp. 11071
Author(s):  
Yutaro Ota ◽  
Tomomichi Ozaki ◽  
Keiji Kubushiro.O
Keyword(s):  
Creep Deformation ◽  
Minimum Creep Rate ◽  
Life Prediction ◽  
Dwell Time ◽  
Room Temperature ◽  
Rupture Life ◽  
Ti Alloys ◽  
Dwell Fatigue ◽  
Strain Change ◽  
Long Time

Titanium a lloys have been found that the fatigue strength of Ti alloys decreases due to cold dwell fatigue (CDF) at room temperature. Ti and Ti alloys generate creep deformation at room temperature (T/Tm = 0.15). Thus, it is considered that creep affects the reduction in fatigue life in CDF tests. This research intends to clarify the effects of long time dwell under tensile stress and rupture life prediction from the view of creep deformation in CDF characteristics of Ti-6Al-4V. Rupture cycle decreased with increase of dwell time. Additionally, lower limit of rupture life ratio “NCDF/NLCF” was defined from rupture in creep test if it was assumed that creep test was extremely long time dwell CDF test. When strain change in whole dwell time was extracted in CDF tests, strain change was like creep curves and minimum creep rate changed depending on dwell time. Minimum creep rate was calculated by the formula based on experimental results, and then rupture time was calculated by Monkman-grant relationship. All of rupture cycle predictions were in factor of 2. Therefore, rupture cycle and time can be calculated if dwell time is known in CDF tests.

scholarly journals Why titanium alloys withstand more strain under dwell-fatigue than under fatigue?

2020 ◽  
Vol 321 ◽  
pp. 11080
Author(s):  
S. Hémery ◽  
A. Naït-Ali ◽  
C. Lavogiez ◽  
P. Villechaise
Keyword(s):  
Crack Initiation ◽  
Plastic Strain ◽  
Room Temperature ◽  
Maximum Stress ◽  
Fourier Transforms ◽  
Stress And Strain ◽  
Cyclic Testing ◽  
Applied Loading ◽  
Dwell Fatigue ◽  
Number Of Cycles

Experimental observations reveal that crack initiation proceeds at a reduced number of cycles if a load hold at maximum stress is introduced during cyclic testing. Although this feature was extensively investigated and stems from the occurrence of room temperature creep, other differences between fatigue and dwell-fatigue behaviors are still to be clarified. In particular, a higher plastic strain is cumulated prior to failure if the load hold is present. This observation highlights differences in the deformation behavior depending on the applied loading. The present article reports an investigation of this point using Fast-Fourier transforms based crystal plasticity simulations of the stress and strain field. Significant differences were evidenced and discussed in light of experimental results reported in the literature. In particular, the occurrence of crack initiation for different cumulated plastic strain depending on the loading conditions is elucidated.

Titanium Alloy Developments For Future Fan Disc Applications – The Fatigue Response of “Alloy 104”

2014 ◽  
Vol 891-892 ◽  
pp. 569-574 ◽  
Author(s):  
Jon S. Hewitt ◽  
Matthew J. Thomas ◽  
Paul Garratt ◽  
Martin R. Bache
Keyword(s):  
Titanium Alloy ◽  
Room Temperature ◽  
High Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Hold Period ◽  
Peak Loads ◽  
Dwell Fatigue ◽  
Load Regime ◽  
Aero Engine

Alloy 104 is a novel high strength, α+β titanium alloy primarily aimed at aero-engine fan disc applications. Two microstructural variants of Alloy 104 have been assessed. Room temperature tensile strength and elongation have been investigated alongside a more detailed study of low and high cycle fatigue behaviour. The alloy clearly demonstrated an improved fatigue resistance in both microstructural conditions, whilst maintaining forgeability and a comparable density to Ti-6Al-4V. Furthermore, the alloy has been subjected to a load regime with a hold period at peak loads and proven to be insensitive to dwell fatigue.

Classification of Textures and Microstructure Stability in Rolled F.C.C. Metals with Grain Interactions

2011 ◽  
Vol 702-703 ◽  
pp. 253-260
Author(s):  
Atish K. Ray ◽  
Bradley J. Diak
Keyword(s):  
Room Temperature ◽  
Rolling Texture ◽  
Deformation Bands ◽  
Key Factors ◽  
Microstructure Stability ◽  
Grain Interaction ◽  
High Purity Aluminum ◽  
Copper Single Crystals ◽  
The Stability

A novel experimental investigation of both high and medium stacking fault energy bi-crystals of aluminum and copper, respectively, show that orientation, grain interaction and material are all key factors in the stability of some ideal rolling texture components. Ideal {110} or {112} orientations obtained from high purity aluminum or copper single crystals were embedded within a {110} crystal orientation of the same material and reduced 60 percent by channel die compression at room temperature. Spatial misorientations developed inside the deformation bands were analyzed using SEM-based EBSD. The presence of long-range orientation gradients in some of the crystals revealed the interacting nature of polycrystalline deformation. From the results it is proposed that f.c.c. polycrystalline grains can be classified according to their stability and susceptibility to deformation: (i) stable and interacting; (ii) unstable and interacting; (iii) stable and non-interacting; (iv) unstable and non-interacting.

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