scholarly journals Study of the Effect of the A206/1.0 wt. % γAl2O3 Nanocomposites Content on the Portevin-Le Chatelier Phenomenon in Al/0.5 wt. % Mg Alloys

2021 ◽  
Vol 5 (6) ◽  
pp. 163
Author(s):  
David Florián-Algarín ◽  
Xiaochun Li ◽  
Hongseok Choi ◽  
Oscar Marcelo Suárez
Keyword(s):  
Strain Aging ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Mg Alloys ◽  
Alumina Nanoparticles ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Ice Water ◽  
Mg Melt

The Portevin-Le Chatelier (PLC) phenomenon or dynamic strain aging in Al–0.5 wt. % Mg alloys was investigated at different strain rates. This research also examined the effect of γAl2O3 nanoparticles on the PLC phenomenon. A nanocomposite made of A206/1.0 wt. % γAl2O3 was manufactured to this purpose and then, added to an Al–0.5 wt. % Mg melt to obtain ingots of Al–0.5 wt. % Mg–20 wt. % A206/1.0 wt. % γAl2O3 and Al–0.5 wt. % Mg–10 wt. % A206/1.0 wt. % γAl2O3 with 6 mm diameter. Cold deformation allowed manufacturing 1 mm diameter wires using the 6 mm diameter ingots. A 300 °C solution treatment, followed by rapid cooling in ice water permitted to retain Mg atoms in solid solution. The tensile tests performed on the wires revealed the PLC phenomenon upon the tensile stress vs. strain plastic zone. The phenomenon was quantified using MatLab™ and statistical analysis. The results demonstrated how the alumina nanoparticles can diminish the serration amplitude of the PLC phenomenon.

scholarly journals Al/Niobium Diboride Nanocomposite’s Effect on the Portevin-Le Chatelier Phenomenon in Al-Mg Alloys

2019 ◽  
Vol 3 (3) ◽  
pp. 70
Author(s):  
David Florián-Algarín ◽  
Michelle Marrero-García ◽  
Javier José Martínez-Santos ◽  
Luis Montejo Valencia ◽  
Oscar Marcelo Suárez
Keyword(s):  
Tensile Deformation ◽  
Solution Treatment ◽  
Signal Amplitude ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Solution Treated ◽  
Cold Rolled ◽  
Ice Water ◽  
Mg Melt ◽  
Al Mg Alloys

In Al-Mg alloys, the Portevin-Le Chatelier phenomenon, or dynamic strain aging, reveals itself as serrations upon plastic tensile deformation. This research evaluates this phenomenon when Al/NbB2 nanocomposite pellets are added to a magnesium-supersaturated Al matrix. A ball-milled 90 wt % Al and 10 wt % NbB2 nanocomposite helped inoculate an Al-Mg melt to incorporate the nanoparticles effectively. The melt was cast into rods that were cold-rolled into 1 mm diameter wires. Two sets were prepared: The first group was an as-cast set of samples, for comparison purposes, whereas the second was a solution-treated set. The solution treatment consisted of annealing followed by ice-water quenching. The results corroborating that the phenomenon was observable only in the specimens bearing the solution treatment, were used as the research baseline. Said treated alloy was compared to one containing the nanoparticles, which proved that the NbB2 particles caused a reduction of the serrated signal amplitude.

Effects of Strain Rate on Dynamic Strain Aging of SA508-III Steel

2014 ◽  
Vol 788 ◽  
pp. 334-339 ◽  
Author(s):  
Dan Yuan ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Jia Hua Liu
Keyword(s):  
Strain Rate ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Cell Structure ◽  
Tensile Tests ◽  
Dislocation Cell ◽  
Strain Rate Range ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Reduction Of Area

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.

scholarly journals A New Explanation for the Effect of Dynamic Strain Aging on Negative Strain Rate Sensitivity in Fe–30Mn–9Al–1C Steel

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3426 ◽  
Author(s):  
Jia Xing ◽  
Lifeng Hou ◽  
Huayun Du ◽  
Baosheng Liu ◽  
Yinghui Wei
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Dislocation Arrangement ◽  
Hall Plot

In this study, the evolution of the mechanical properties of Fe–30Mn–9Al–1C steel has been determined in tensile tests at strain rates of 10−4 to 102 s−1. The results show that the strain rate sensitivity becomes a negative value when the strain rate exceeds 100 s−1 and this abnormal evolution is attributed to the occurrence of dynamic strain aging. Due to the presence of intergranular κ-carbides, the fracture modes of steel include ductile fracture and intergranular fracture. The values of dislocation arrangement parameter M were obtained using a modified Williamson–Hall plot. It has been found that once the strain rate sensitivity becomes negative, the interaction of dislocations in the steel is weakened and the free movement of dislocation is enhanced. Adiabatic heating promotes the dynamic recovery of steel at a high strain rate.

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
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Magnesium Alloy ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Solution Treatment ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Az91d Magnesium Alloy ◽  
Solute Atoms

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.

Influence of Rate of Strain and Temperature on Yield Stresses of Mild Steel

1944 ◽  
Vol 11 (4) ◽  
pp. A211-A218
Author(s):  
M. J. Manjoine
Keyword(s):  
Mild Steel ◽  
Yield Stress ◽  
Strain Aging ◽  
Room Temperature ◽  
Tensile Tests ◽  
Ultimate Stress ◽  
Strain Rates ◽  
Discontinuous Yielding

Abstract This paper describes the influence of rate of strain and temperature on the yield stresses of mild steel. Tensile tests are reported for room temperature, 200, 400, and 600 C, at rates of strain which vary from 10−8 to 103 per sec. The results of these tensile tests are plotted to show more clearly the effects of strain-aging on the yield stresses and ultimate stress. The comparison of the yield stress at various strain rates permits an analysis of the influence of strain. The conditions necessary for discontinuous yielding are described and compared with test experiences.

Investigation of Dynamic Strain Ageing Effects of Low Alloy Steels 15Kh2MFA and 15Kh2NMFA

2005 ◽  
Vol 482 ◽  
pp. 367-370
Author(s):  
Miroslava Ernestová
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Low Alloy Steels ◽  
Strain Rates ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Lower Strain ◽  
Wide Range ◽  
Alloy Steels

The paper summarizes results of tensile tests in low alloy steel (LAS) specimens (steels 15Kh2MFA and 15Kh2NMFA). Slow Strain Rate Tensile tests (SSRT) were performed in air at temperatures from 22 to 325°C over a wide range of strain rates from 2.5×10-6 to 1.67×10-3 s-1. The possible effect of strain rate and temperature to mechanical properties of tested LAS is searched for. The dynamic strain ageing (DSA) was observed within certain temperature ranges at lower strain rates tested and its hardening effect in terms of the maximum strengthening stress decreased linearly with the increase of log strain rate. It has been found that the occurrence of susceptibility to environmentally assisted cracking (EAC) of tested steels in high temperature water (HTW) is corelated to the DSA behavior. The result suggest that DSA reduces ductility of reactor pressure vessel (RPV) steel and its role in enhancing the EAC of RPV steels should not be neglected, in view of the coincidence with susceptibility zones for DSA and EAC in terms of strain rate and temperature. A reasonable coincidence was observed between the susceptibility to DSA exhibited by SSRT in air and with the EAC behavior observed in laboratory experiments.

EFFECT OF SOLUTION TREATMENT ON THE INVERSE DYNAMIC STRAIN AGING OF A Ni-Co BASE SUPERALLOY

2012 ◽  
Vol 48 (10) ◽  
pp. 1223 ◽  
Author(s):  
Chenggang TIAN ◽  
Chuanyong CUI ◽  
Yuefeng GU ◽  
Xiaofeng SUN
Keyword(s):  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Solution Treatment ◽  
Dynamic Strain ◽  
Inverse Dynamic ◽  
Base Superalloy
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