Effect of SPD processing on mechanical behavior and dynamic strain aging of an Al-Mg alloy in various deformation modes and wide strain rate range

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.

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Temperature and strain rate dependence of the dynamic strain aging effect in an Al–Zn–Mg alloy

Materials Science and Technology ◽

10.1179/174328406x74284 ◽

2006 ◽

Vol 22 (2) ◽

pp. 213-222 ◽

Cited By ~ 7

Author(s):

M. Hörnqvist ◽

B. Karlsson

Keyword(s):

Strain Rate ◽

Dynamic Strain Aging ◽

Strain Aging ◽

Aging Effect ◽

Rate Dependence ◽

Strain Rate Dependence ◽

Mg Alloy ◽

Dynamic Strain

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Behavior of Dynamic Strain Aging in Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr Alloy Strip

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2021.59.1.8 ◽

2021 ◽

Vol 59 (1) ◽

pp. 8-13

Author(s):

Il-Hyun Kim ◽

Myung-Ho Lee ◽

Yang-Il Jung ◽

Hyun-Gil Kim ◽

Jae-Il Jang

Keyword(s):

Tensile Test ◽

Strain Rate ◽

Dynamic Strain Aging ◽

Strain Aging ◽

Rolling Direction ◽

Rate Sensitivity ◽

Dynamic Strain ◽

Alloy Strip ◽

Lower Strain ◽

Temperature Ranges

The behavior of dynamic strain aging (DSA) in a Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr alloy strip was investigated at temperature ranges of 25–600 °C via a tensile test. The tensile test was performed at two different strain rates 8.33 × 10-5 and 1.67 × 10-2 s-1. The shear stress of the alloy strip revealed a linear dependency on the test temperature when the specimens were tested under a higher strain rate (1.67 × 10-2 s-1). However, the linear relationship was broken due to DSA when the samples were deformed under a lower strain rate (8.33 × 10-5 s-1). The discrepancy was most significant at 400 °C. The trend in DSA behavior was similar irrespective of the orientation of the samples, i.e., rolling direction (RD) or transverse direction (TD). However, the effect of DSA was larger in the TD samples than the RD samples. The phenomena were interpreted to the variation in work hardening exponents and strain rate sensitivity. The value of the exponent decreased from 0.14 to 0.08 along a RD and from 0.1 to 0.07 along a TD, respectively. However, the smallest value was observed at 400–500 °C irrespective of the specimen orientation, which is consistent with the DSA behavior. It is suggested that the DSA was caused by an interaction of moving dislocations with solute atoms typically oxygen.

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