Formation of submicrometre-grained structure in magnesium alloy due to high plastic strains

1990 ◽  
Vol 9 (12) ◽  
pp. 1445-1447 ◽  
Author(s):  
R. Z. Abdulov ◽  
R. Z. Valiev ◽  
N. A. Krasilnikov
Keyword(s):  
Magnesium Alloy ◽  
Plastic Strains ◽  
High Plastic

Modification Strain-Based Failure Assessment Diagram for High Strength Pipeline Steel

2016 ◽  
Vol 853 ◽  
pp. 33-40
Author(s):  
Jun Lin Shi ◽  
Jian Ping Zhao ◽  
Wei Jie Jiang
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Pipeline Steel ◽  
High Strength ◽  
Plastic Strains ◽  
Failure Assessment Diagram ◽  
Failure Assessment ◽  
High Plastic

The strain-based failure assessment diagram (SB-FAD) has been developed to predict failure due to high plastic strains. This paper validates the SB-FAD by finite element results for high strength pipeline steel (X80, X80HD, and X90) with four representative specimens (CT, CCP, DECP, and SCEP) of different crack sizes, respectively. The influence of material properties, geometries and crack sizes on failure assessment curves were compared and analyzed. Meanwhile, the modified Option-1 curve of SB-FAD is given in this paper. The results showed that the modified Option-1 curve of SB-FAD is more accurate when the value of abscissais Dr small and more conservative when the value of abscissa Dr is large.

Failure Prediction of Curved Wide Plates Using the Strain-Based Failure Assessment Diagram With Correction for Constraint and Notch Radius

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Anthony Horn ◽  
Mikhail Trull ◽  
Stijn Hertelé
Keyword(s):  
Fatigue Crack ◽  
Experimental Approach ◽  
Fatigue Cracks ◽  
Failure Prediction ◽  
Plastic Strains ◽  
Notch Radius ◽  
Failure Assessment Diagram ◽  
Failure Assessment ◽  
Low Constraint ◽  
High Plastic

The strain-based failure assessment diagram (SB-FAD) has been developed for predicting failure from flaws in components subjected to high plastic strains. In this paper, a combined numerical and experimental approach is used to apply the SB-FAD to predict failure from a series of API 5L grades X80 and X100 curved wide plate (CWP) specimens with shallow notches machined into the pipe girth weld. For the CWP specimens tested in this work, the SB-FAD in its unmodified form resulted in over-conservative predictions of failure. This is attributed to the SB-FAD assuming high constraint conditions and the presence of a sharp fatigue crack, whereas the CWP specimens tested in this work were low constraint and contained a shallow machined notch without fatigue cracks. A modification of the SB-FAD is then proposed to account for nonsharp defects loaded to high plastic strains under conditions of low constraint. The resulting predictions of the modified SB-FAD show significantly reduced conservatism compared to the unmodified SB-FAD.

Enhanced Plastic Deformation of Magnesium Alloy Produced through Accumulative Diffusion Bonding

2012 ◽  
Vol 735 ◽  
pp. 87-92 ◽  
Author(s):  
Koichi Kitazono ◽  
Yutaro Shimoda ◽  
Shigeki Kato
Keyword(s):  
Plastic Deformation ◽  
Magnesium Alloy ◽  
Diffusion Bonding ◽  
Alloy Sheet ◽  
Az91 Magnesium Alloy ◽  
Bending Tests ◽  
Random Texture ◽  
Az91 Magnesium ◽  
Hcp Structure ◽  
High Plastic

Plastic deformation of magnesium alloy is limited because of its HCP structure. Though the grain refined magnesium alloy exhibits superplastic deformation at elevated temperature, the strength decreases due to induced cavitation. This study focusses on developing the random texture of magnesium alloy and causes relatively high plastic deformation even at room temperature. Random texture is produced through newly proposed accumulative diffusion bonding process using commercial AZ91 magnesium alloy sheets. Tensile and V-bending tests reveal that the enhanced ductility of the produced magnesium alloy sheet.

Failure Prediction of Curved Wide Plates Using the Strain-Based Failure Assessment Diagram With Correction for Constraint and Notch Radius

2013 ◽  
Author(s):  
Anthony J. Horn ◽  
Mikhail Trull ◽  
Stijn Hertelé
Keyword(s):  
Fatigue Crack ◽  
Experimental Approach ◽  
Fatigue Cracks ◽  
Failure Prediction ◽  
Plastic Strains ◽  
Notch Radius ◽  
Failure Assessment Diagram ◽  
Failure Assessment ◽  
Low Constraint ◽  
High Plastic

The strain-based failure assessment diagram (SB-FAD) has been developed for predicting failure from flaws in components subjected to high plastic strains. In this paper, a combined numerical and experimental approach is used to apply the SB-FAD to predict failure from a series of API 5L grades X80 and X100 curved wide plate (CWP) specimens with shallow notches machined into the pipe girth weld. For the CWP specimens tested in this work, the SB-FAD in its unmodified form resulted in over-conservative predictions of failure. This is attributed to the SB-FAD assuming high constraint conditions and the presence of a sharp fatigue crack, whereas the CWP specimens tested in this work were low constraint and contained a shallow machined notch without fatigue cracks. A modification of the SB-FAD is then proposed to account for non-sharp defects loaded to high plastic strains under conditions of low constraint. The resulting predictions of the modified SB-FAD show significantly reduced conservatism compared to the unmodified SB-FAD.

Investigation of grain subdivision at very low plastic strains in a magnesium alloy

2017 ◽  
Vol 693 ◽  
pp. 14-21 ◽  
Author(s):  
X. Hong ◽  
A. Godfrey ◽  
C.L. Zhang ◽  
W. Liu ◽  
A. Chapuis
Keyword(s):  
Magnesium Alloy ◽  
Plastic Strains

Application of Separated Die Design to Production of Ecap Dies

2012 ◽  
Vol 445 ◽  
pp. 120-124 ◽  
Author(s):  
Huseyin Erol Akata
Keyword(s):  
Metal Forming ◽  
Die Design ◽  
Shear Stresses ◽  
Notch Effect ◽  
Plastic Strains ◽  
Alloy Specimen ◽  
Equal Channel Angular Processing ◽  
High Plastic ◽  
5083 Aluminum Alloy ◽  
Very High

Metal forming processes with principally shear stresses that very high plastic strains are obtained in one pass are defined as severe plastic deformation (SPD) processes. Strain values can additionally be increased with additional passes throughout the process. Equal channel angular processing (ECAP) is the most applied method among the SPD processes due to relative ease of die manufacturing. On the other hand, die failures like corner cracking are frequently observed due to high notch effect and therefore use of the dies is limited. In the presenting study multi element die design (separated die design) approach was applied to production of ECAP dies in order to eliminate die failures and 5083 Aluminum alloy specimen were deformed with several passes. Although some additional development for die arrangement and fixation are needed, corner cracking was never observed and dies could be used safely.

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