Study on Dynamic Strain Aging Phenomenon of AZ91D Magnesium Alloy

2012 ◽  
Vol 472-475 ◽  
pp. 2962-2965 ◽  
Author(s):  
Na Lin ◽  
Kai Huai Yang ◽  
Shao Feng Zeng ◽  
Wen Zhe Chen

Tensile experiment of AZ91D magnesium alloy was carried out and serrated flow was apparent throughout the deformation history. Dynamic strain aging (DSA) occurs when the AZ91D magnesium alloy treated by solid solution treatment has been deformed at a set range of strain rates (1.11×10-4 s-1 to1.67×10-3 s-1) and a certain range temperatures (248 K to 423 K). The critical plastic strain εc was observed to increase with increasing strain rates but decrease with increasing temperature. The diffusing activation energy of solute atoms during the DSA occurring in AZ91D magnesium alloy is 140.8 kJ/mol by calculating, which is correspondence match with the diffusing activation energy of Al solute atoms in Mg matrix. Therefore, the micro-mechanism of DSA in the alloy is believed that the Al atoms in solid solution gather around dislocations to form Cottrell solute atmospheres by vacant diffusion and then pin the moving dislocations.

2017 ◽  
Vol 97 (6) ◽  
pp. 235-240 ◽  
Author(s):  
W. H. Wang ◽  
D. Wu ◽  
S. S. Shah ◽  
J. H. Ni ◽  
R. S. Chen ◽  
...  

2008 ◽  
Vol 61 (4) ◽  
pp. 301-306 ◽  
Author(s):  
M. Shanmugavel ◽  
M. Nandagopal ◽  
R. Sandhya ◽  
K. Bhanu Sankara Rao ◽  
R. Gnanamoorthy

2013 ◽  
Vol 652-654 ◽  
pp. 1937-1941 ◽  
Author(s):  
Si Qian Zhang ◽  
Liang Mao ◽  
Li Jia Chen

Serrated flow has been observed in AZ81 alloy during tensile deformation. The observed static strain ageing effect and negative strain rate sensitivity suggest that the serrated flow is due to interaction between dislocations and solute atoms, know as dynamic strain ageing (DSA). The Portevin-Le Chatelier effect is observed at temperatures between 150oC~200oC and 125oC~200oC. In the microstructure of deformed samples dislocations and twins is observed. It is suggested that the occurrence of the dynamic strain aging is associated with interactions between solute atoms and dislocations.


2014 ◽  
Vol 788 ◽  
pp. 334-339 ◽  
Author(s):  
Dan Yuan ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Jia Hua Liu

The dynamic strain aging (DSA) behavior of SA508-III steel was evaluated through tensile tests with different strain rates from 10-4 to 10-1s-1 at 350°C. The OM, SEM and TEM were carried out to observe the microstructures and fracture morphologies of the steel. The results show that the serrated flows appear in the stress-strain curves when the strain rate is between 10-3~10-2s-1, indicating that DSA occurs. Under the strain rate range, the tensile strength increases and the elongation and the reduction of area decrease. However, the fracture surface of the steel after tensile tests is still ductile. DSA in SA508-III steel at the strain rates from10-3 to 10-2s-1 is mainly caused by the interaction between the internal solute atoms and dislocations, which leads to the dislocations multiplication and the formation of sub-grain boundaries and dislocation cell structure.


2012 ◽  
Vol 48 (10) ◽  
pp. 1223 ◽  
Author(s):  
Chenggang TIAN ◽  
Chuanyong CUI ◽  
Yuefeng GU ◽  
Xiaofeng SUN

1983 ◽  
Vol 76 (2) ◽  
pp. 609-614 ◽  
Author(s):  
G. H. van Haastert ◽  
A. van den Beukel

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