OS1115 Control of high-cycle fatigue fracture based on grain boundary engineering in SUS316L stainless steels

2014 ◽  
Vol 2014 (0) ◽  
pp. _OS1115-1_-_OS1115-2_
Author(s):  
Shigeaki KOBAYASHI ◽  
Satoshi OGOU
Keyword(s):  
Grain Boundary ◽  
Fatigue Fracture ◽  
Stainless Steels ◽  
High Cycle Fatigue ◽  
Grain Boundary Engineering ◽  
Cycle Fatigue

Study on Fatigue Behaviors of 0Cr21Mn17Mo2N0.83 High Nitrogen Stainless Steels

2020 ◽  
Vol 861 ◽  
pp. 89-94
Author(s):  
You Yang ◽  
Wei Feng Tang
Keyword(s):  
Solid Solution ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Fracture ◽  
Stainless Steels ◽  
Room Temperature ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
High Nitrogen

High cycle fatigue behaviors of 0Cr21Mn17Mo2N0.83 high nitrogen stainless steels at forged and solid solution state were investigated. High cycle fatigue tests were carried out up to 107cycles at a stress ratio R=0.1 and frequency of 70Hz on specimens using a high frequency fatigue machine. Fatigue fracture surfaces of specimens that in the high cycle fatigue tests were observed using a scanning electron microscope for revealing the micro-mechanisms of fatigue crack initiation and propagation. The results showed that the fatigue limit of test alloys at room temperature is 865.25 MPa (as-forged alloy) and 736.10MPa (solid solution alloy), respectively. The micro-fatigue fracture surface of the test alloys included three representative regions. These regions are fatigue initiation area, fatigue crack propagation area and fatigue fracture area. Fatigue cracks of the test alloys initiate principally at the precipitates, inclusion or uneven stress concentration sites of alloy surface, and propagate along the grain boundary. The fatigue striations of fatigue crack propagation area are very clear. The fatigue fracture of test specimens show the rupture characteristics of quasi cleavage and dimple fracture. The room temperature fatigue properties of as-forged alloy are generally higher than that of the solid solution high nitrogen stainless steel according to the S-N curves fitting results.

Investigation on Fatigue Damage of the Al5Zn2Mg High Strength Aluminum Alloy

2013 ◽  
Vol 721 ◽  
pp. 12-15 ◽  
Author(s):  
Xian Liang Sun ◽  
Ai Qin Tian ◽  
Wen Bin Chen ◽  
San San Ding ◽  
Shang Lei Yang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Grain Boundary ◽  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Alloy Sample ◽  
Cycle Fatigue ◽  
High Strength Aluminum Alloy ◽  
Propagation Zone

The fatigue fracture and the microstructure of Al5Zn2Mg high strength aluminum alloy were observed by OM, SEM and TEM, and the low cycle fatigue properties were tested and analyzed. The results of experimentation show that the low cycle fatigue life of Al5Zn2Mg high strength aluminum alloy is 9.28×104 cycle in R=0.1, f=8Hz, and σmax=0.75σb. The tensile strength is 444MPa. The fatigue fracture is composed of the initiation zone, the propagation zone, and the sudden fracture zone, which is characteristic of a mixed-type fatigue fracture. The fatigue crack initiates in the surface of Al5Zn2Mg aluminum alloy sample, while there is no fatigue striation in fatigue crack propagation zone. The η′(MgZn2) transitional strengthening phases are precipitated in Al5Zn2Mg aluminum alloy, and mostly distributed in grain boundary. The diameter of η′ strengthening phase is fine, about is 10nm. There is none precipitated zone in width nearby the grain boundary

Fatigue of Stainless Steel Components: Toward Codified Rules Improvements

2013 ◽  
Author(s):  
Claude Faidy
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Environmental Effects ◽  
Stainless Steels ◽  
High Cycle Fatigue ◽  
Fatigue Curve ◽  
Fatigue Tests ◽  
Correction Factors ◽  
Cycle Fatigue ◽  
The Past

During the past 30 years many fatigue tests and fatigue analysis improvements have been developed in France in order to improve Codified Fatigue Rules of French Nuclear Codes: RCC-M, RSE-M and RCC-MRx. This paper will present comments and proposals for development of these rules associated to Gaps and Needs in order to finalize and justify the AFCEN Codes new rules. Recently 3 new international R&D results confirm possible un-conservative fatigue material data: - High cycle fatigue in air for stainless steel, - Environmental effects on fatigue S-N curve for all materials, and in particular stainless steels, - Fatigue Crack Growth law under PWR environment for stainless steel. In front of these new results, AFCEN is working on a 1st set of rules based on existing knowledge: - Air fatigue curve: mean and design - PWR Environmental effects with detrimental correction factors A periodic up-dating of AFCEN proposed rules will be done using French and International R&D programs with a particular attention on harmonization with other Code rules developed in USA, Japan and Germany, in particular.

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