Effects of solidification structure on fatigue crack initiation and fatigue strength in Al−Si−Mg cast alloys

2002 ◽  
Vol 8 (5) ◽  
pp. 443-447 ◽  
Author(s):  
Sang-Won Han ◽  
Ui-Jong Lee ◽  
Sug-Won Kim
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Fatigue Crack Initiation ◽  
Solidification Structure ◽  
Cast Alloys

Effect of Processing Layer on Fatigue Strength of Extruded AZ61 Magnesium Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 429-432 ◽  
Author(s):  
Yukio Miyashita ◽  
Kyohei Kushihata ◽  
Toshifumi Kakiuchi ◽  
Mitsuhiro Kiyohara
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Crack Growth Resistance ◽  
Az61 Magnesium Alloy

Fatigue Property of an Extruded AZ61 Magnesium Alloy with the Processing Layer Introduced by Machining was Investigated. Rotating Bending Fatigue Tests were Carried out with the Specimen with and without the Processing Layer. According to Results of the Fatigue Tests, Fatigue Life Significantly Increased by Introducing the Processing Layer to the Specimen Surface. Fatigue Crack Initiation and Propagation Behaviors were Observed by Replication Technique during the Fatigue Test. Fatigue Crack Initiation Life of the Specimen with the Processing Layer was Slightly Longer than that of the Specimen without the Processing Layer. Higher Fatigue Crack Growth Resistance was also Observed when the Fatigue Crack was Growing in the Processing Layer in the Specimen with the Processing Layer. the Longer Fatigue Life Observed in the Fatigue Test in the Specimen with the Processing Layer could be Mainly due to the Higher Crack Growth Resistance. it is Speculated that the Fatigue Strength can be Controlled by Change in Condition of Machining Process. it could be Effective way in Industry to Improved Fatigue Strength only by the Cutting Process without Additional Surface Treatment Process.

scholarly journals Fatigue Strength and Fatigue-Crack Initiation of Ti-6Al-4V Alloy.

1993 ◽  
Vol 42 (481) ◽  
pp. 1179-1185 ◽  
Author(s):  
Shin-ichi NISHIDA ◽  
Chikayuki URASHIMA ◽  
Noriyuki TAKANO
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Fatigue Crack Initiation

Development of Structural Steel With High Resistance to Fatigue Crack Initiation and Growth: Part 3

2005 ◽  
Author(s):  
Hiroshi Katsumoto ◽  
Noboru Konda ◽  
Kazushige Arimochi ◽  
Kazuhiro Hirota ◽  
Atsushi Isoda ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Crack Initiation ◽  
Fatigue Fracture ◽  
High Resistance ◽  
Fatigue Crack Initiation ◽  
Conventional Steel ◽  
Welded Structure ◽  
Safety And Reliability

In recent years, higher safety and reliability of steel welded structures have been required as it shows growing concern about environmental problems. To prevent fatigue fracture is one of the most important challenges to improve the safety and reliability. A lot of studies how reduce stress concentration at critical areas have been carried out from the viewpoint of structural design as prevention measures while nothing has been studied from the viewpoint of material because fatigue strength of welded joints converges in limited range regardless of material strength. On the other hand, it was found that an appropriate dual phase microstructure could reduce the fatigue crack growth rate remarkably. The newly developed steel plate with high resistance to fatigue crack growth could extend the fatigue life of structures. The developed steels have already been applied to some ships and vessels, and a new bulk carrier applied the developed steels acquired the notation and descriptive note as the valuable ship with resistance to fatigue fracture by Nippon Kaiji Kyokai for the first time in the world. From further studies, it was found the developed steels had also high resistance to fatigue crack initiation as well as the growth even in welded structure. In this study, it was clarified that the fatigue strength of HAZ, where fatigue crack generally initiates, in the developed steel was higher than that in conventional steel and the stress concentration at toe of weld in the developed steel was smaller than in the conventional steel. It was considered the mechanism of suppression of fatigue crack initiation with FEM analysis and fatigue test. The newly developed steel can effectively extend fatigue fracture life of welded structure from the viewpoint of material.

Ultrasonic Corrosion Fatigue Behaviorof Duplex Stainless Steel

2013 ◽  
Vol 577-578 ◽  
pp. 421-424 ◽  
Author(s):  
Ryuichiro Ebara ◽  
Yuya Miyoshi
Keyword(s):  
Aqueous Solution ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Corrosion Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Corrosion Fatigue Crack ◽  
Corrosion Fatigue Strength ◽  
Corrosion Pit

Ultrasonic Corrosion Fatigue Tests were Conducted for SUS329J3L in Air and 3%NaCl Aqueous Solution. Reduction of Giga-Cycle Corrosion Fatigue Strength was 12.5%. Corrosion Pit was Observed on Corrosion Fatigue Crack Initiation Area. Striation was Predominantly Observed on Crack Propagation Area both in Air and 3% Nacl Aqueous Solution. it can be Concluded that the Reduction of Corrosion Fatigue Strength of SUS329J3L is due to the Corrosion Pit Formation at Corrosion Fatigue Crack Initiation Area.

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