Influential Factors on the Formation of Initial Crack Propagation Region in Sub-surface Fracture of Ti-6Al-4V Alloy

博幸, 小熊; 孝, 中村

doi:10.2472/jsms.60.1072

Cited by 3 publications

(14 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 29B indicates the high magnification SEM observation within the area of ODA, which shows the characteristic fine granular morphology. On the formation mechanism of such a characteristic morphology inside the ODA, Nakamura et al had proposed their original model as shown in Figure 30 60,61 . If the crack grows in air, gas molecules enter in the cracked space easily, and some chemical reaction would be caused along the cracked surface.…”

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

“…Since the crack growth around the interior inclusion takes place in vacuum, the cracked surface would be re‐bonded at some sites during the instance of compression as shown in Figure 30②. Nakamura et al had called this re‐bonding as cold‐welding 60 . Re‐bonded portion would be debonded along other path.…”

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

“…An example of SEM observation of fracture surface in interior induced fracture 60 . (A) ODA around inclusion.…”

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

“…In the VHCF of metallic materials, the meaning of the conventional fatigue limit has been often discussed and the duplex S–N characteristics are sometimes reported on high strength steels as introduced in Section 4.1. An important fact is that the fatigue fracture is usually caused by interior inclusion in the very high cycle regime 37,38,42,44–52,58,60 . Thus, a particular attention has been focused to the existence of the threshold value to initiate the crack growth from the interior inclusion.…”

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

See 3 more Smart Citations

Historical review and future prospect for researches on very high cycle fatigue of metallic materials

Sakai

2023

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

Since the first paper on the fatigue of metallic materials by J. Albert in 1837, tremendous numbers of papers have been published in various journals by many researchers all over the world. Based on such a long history, several papers on the very high cycle fatigue (VHCF) in the life-time longer than 10 7 cycles had appeared in some journals during the period of 1980's. One characteristic finding in these works is the fact that the metallic material can fail even at the stress level lower than the conventional fatigue limit. This fact means that the conventional fatigue design of mechanical structures cannot give the safety of the practical products in the very high cycle regime. Due to this fact, fatigue properties of structural materials in very long life regime has become an important subject; and a lot of studies have been carried out, and many important results have been accumulated until now. Typical aspects on VHCF property are summarized as follows: (1) the fatigue crack tends to occur around the interior inclusion, (2) fine granular area (FGA) is formed around such an inclusion, and (3) duplex S-N characteristics appear in the VHCF regime. In this paper, a brief historical review together with the future prospect on the very high cycle fatigue of metallic materials is attempted for the sake of reference to facilitate the research in this area.

show abstract

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

“…An example of SEM observation of fracture surface in interior induced fracture 60 . (A) ODA around inclusion.…”

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

Section: Brief Review For Researches On Vhcfmentioning

confidence: 99%

See 2 more Smart Citations

Historical review and future prospect for researches on very high cycle fatigue of metallic materials

Sakai

2023

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…In Ref. 28), Ti-6Al-4V alloy (wrought material) was fatigue-tested under vacuum conditions. According to this reference, oxygen absorption on the fresh slip planes and newly formed crack surfaces was suppressed under the vacuum conditions, so that reverse slips and re-adhesion of crack surfaces were induced.…”

Section: Fatigue Propertiesmentioning

confidence: 99%

Fundamental Properties of Ti-6Al-4V Alloy Produced by Selective Laser Melting Method

et al. 2017

View full text Add to dashboard Cite

This study was conducted to comprehensively investigate the fundamental properties of Ti-6Al-4V alloy produced by the selective laser melting (SLM) method. The examined materials were three SLM materials having different axial directions. For comparison, wrought material of Ti-6Al-4V alloy was also examined. The results showed that the densities of the SLM materials were adequately high and more than 99.9% of that of the wrought material. The SLM materials possessed a columnar microstructure extending along the building direction. This microstructure was mainly composed of the acicular α martensite phase. Due to the generation of the ne α phase, the static strength of the SLM materials was markedly higher than that of the wrought material although their elongation was lower. There was anisotropy in the static strength and the ductility of the SLM materials. In spite of the higher tensile strength, the fatigue strength of the SLM materials was much lower than that of the wrought material since molding defects may induce stress concentration and accelerate the generation of fatigue cracks.

show abstract

Factors Affecting Strength in Surface and Sub-Surface Fracture of Ti-6Al-4V Alloy

博幸¹,

孝²

2013

J. Soc. Mat. Sci., Japan

View full text Add to dashboard Cite

To reveal influence factors on the very high cycle fatigue properties of Ti-6Al-4V alloy, uni-axial fatigue tests and fatigue crack propagation tests were conducted. In the uni-axial fatigue tests, specimens with artificial defects of several sizes were used. Both tests were performed in air and vacuum environments. The effects of environments around fatigue cracks on crack propagation properties were investigated. As a results, fatigue crack propagation rates in vacuum were lower than those in air, and the results correspond to the fact that the sub-surface fractures occur in longer life regime than surface fractures. The threshold stress intensity factor range showed size dependencies, in addition, the difference of environments affected the size dependencies. The dependence in vacuum was stronger than in air. The result indicates that a small crack (size of a crack origin) can propagate in lower stress intensity factor ranges in vacuum, and this can relate to the reason why the sub-surface fractures occur in lower stress levels than the surface fractures. Fracture surface observations revealed that fine convex-concave granular pattern (Granular region) was formed around the origins of surface fractures in the vacuum environment, and the aspect resembled the fracture surface of sub-surface fractures. The result showed that the crack propagation mechanism in vacuum and sub-surface of materials were similar. The effects of vacuum environment are almost same as those of environment around the sub-surface crack. The effects of environments around fatigue cracks can well explain the very high cycle fatigue properties of the material.

show abstract

Influential Factors on the Formation of Initial Crack Propagation Region in Sub-surface Fracture of Ti-6Al-4V Alloy

Cited by 3 publications

References 10 publications

Historical review and future prospect for researches on very high cycle fatigue of metallic materials

Historical review and future prospect for researches on very high cycle fatigue of metallic materials

Fundamental Properties of Ti-6Al-4V Alloy Produced by Selective Laser Melting Method

Factors Affecting Strength in Surface and Sub-Surface Fracture of Ti-6Al-4V Alloy

Contact Info

Product

Resources

About