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.

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.

Effect of Cu Content on the Formability and Portevin-Le Chatelier Effect of Al-Mg Alloys

2015 ◽  
Vol 817 ◽  
pp. 150-157
Author(s):  
Peng Cheng Ma ◽  
Di Zhang ◽  
Lin Zhong Zhuang ◽  
Ji Shan Zhang
Keyword(s):  
Plastic Strain ◽  
Stress Drop ◽  
Strain Ratio ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Plastic Strain Ratio ◽  
Cu Content ◽  
Al Mg Alloys

Al-Mg alloys developed for auto body sheets with different Cu contents were fabricated in the laboratory scale. The effects of Cu content on the microstructures, formability and Portevin–Le Chatelier(PLC) effect of the alloys were investigated by polarizied optical microscopy and room temperature tensile testing. It has been found that with increasing Cu content, there was little change of the strain hardening exponent, but the plastic strain ratio and limiting drawing ratio increased firstly and then decreased. A quantitative statistical analysis of the characteristics of the PLC effect was made, including the stress drop and the reloading time, which follow a common linear relationship with plastic strain, and the increase rate of stress drop and reloading time was bigger with more Cu content. A detailed discussion of the corresponding mechanism of Cu and Cu-containing precipitates on the dynamic strain aging(DSA) was made.

Solute concentration dependence of strength and plastic instabilities in Al-Mg alloys

2005 ◽  
Vol 20 (2) ◽  
pp. 331-337 ◽  
Author(s):  
Gy. Horváth ◽  
N.Q. Chinh ◽  
J. Lendvai
Keyword(s):  
Dislocation Line ◽  
Solute Concentration ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Solute Content ◽  
Serrated Flow ◽  
Indentation Tests ◽  
Power Law Function ◽  
Chatelier Effect ◽  
Al Mg Alloys

Characteristics of the dynamic strain aging (DSA) in the Portevin-Le Chatelier effect are experimentally investigated by dynamic indentation tests and numerically analyzed by using literature models. Experimental results obtained on Al–Mg alloys show that the occurrence and development of the plastic instabilities—serrated indentation—depend strongly on the solute content. During dynamic microindentation tests the amplitude of microhardness drops—similarly to the global hardness—and is changing as a power law function of Mg solute content with an exponent of 2/3. It has been shown that the term describing the effect of DSA in serrated flow is not proportional but rather a power expression of the local solute concentration, Cs, on the dislocation line with the exponent of 1/2. Together with this, the kinetics of solute segregation during DSA is controlled by the pipe diffusion.

scholarly journals THE INFLUENCE OF SOLUTION TREATMENT ON THE STRUCTURE AND MECHANICAL AND TRIBOLOGICAL PROPERTIES OF MAGNESIUM ALLOY WE54

Tribologia ◽  
2016 ◽  
Vol 267 (3) ◽  
pp. 19-28 ◽  
Author(s):  
Adam BARYLSKI ◽  
Krzysztof ANIOŁEK ◽  
Michał DWORAK
Keyword(s):  
Magnesium Alloy ◽  
Tribological Properties ◽  
Solution Treatment ◽  
Hot Water ◽  
Linear Wear ◽  
Mechanical And Tribological Properties ◽  
Solution Treated ◽  
Ice Water ◽  
Temperature Water ◽  
Ball On Disc

The paper presents the influence of solution treatment on the mechanical and tribological properties of the WE54 magnesium alloy. The investigated alloy was solution treated at a temperature of 545oC for 8 hours and cooled in ice water (0oC), in room temperature water (20oC), and in hot water (95oC). Depending on the applied solution treatment parameters, a diversified decrease in hardness and Young's modulus was obtained. The lowest values of hardness H and modulus E were obtained when cooling in ice water. Abrasive wear of alloy WE54 was tested using a ball-on-disc tribometer (with a ZrO2 ball). The tests have shown more than a threefold reduction in the volumetric wear and a twofold reduction in the linear wear, as well as favourable changes of the friction coefficient (a 20% decrease) as compared to the material in the as-received condition.

A TEM study of discontinuous precipitation in Cu-Be alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 656-657
Author(s):  
Joseph R. Michael
Keyword(s):  
Electron Microscope ◽  
Grain Boundary ◽  
Single Phase ◽  
Discontinuous Precipitation ◽  
Solution Treatment ◽  
Discontinuous Precipitate ◽  
Boundary Precipitate ◽  
Solution Treated ◽  
Water Quench ◽  
Ice Water

It is known that a lamellar discontinuous precipitate forms in aged Cu-1.8wt.% Be alloys. The purpose of this study was to investigate factors which influence the formation of the precipitate and to characterize its growth.To determine the effect of solution treatment on the discontinuous precipitate, specimens were solution treated at 800°C, 850°C, and 900°C for 1 hour followed by an ice water quench. Some of the solution treated specimens were examined in the as-quenched condition. The remaining specimens were aged at 340°C for 24 hours. The specimens were thinned with a twin-jet electropolishing unit using 30% HNO3 in methanol at -60°C. The specimens were then examined using either an RCA-EMU3G or a Philips EM-300 electron microscope.Each solution treated specimen was not single phase, but showed some residual grain boundary precipitate which implies that the solution anneal was not sufficient, or else precipitation had occurred during quenching. The higher solution treatment temperatures slightly reduced the amount of this grain boundary precipitate, but none completely removed it, even after five hours at temperature,indicating quench decomposition as the mechanism responsible.

Microstructure and Shape Memory Behavior of Ti-18Nb-6Zr (at.%) Alloy

2021 ◽  
Vol 1016 ◽  
pp. 1368-1373
Author(s):  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui
Keyword(s):  
Shape Memory ◽  
Tensile Deformation ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Martensite Phase ◽  
Air Cooling ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Transmission Electron ◽  
Cold Rolled

The microstructures and shape memory behaviors of Ti-18Nb-6Zr (at.%) alloy subjected to different heat treatments were investigated through optical microscopy (OM), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and tensile tests. Recrystallization occurs in cold-rolled Ti-18Nb-6Zr alloy after solution treatment at 600~800 °C. The cooling rate after solution treatment at 800°C shows a dramatic effect on the microstructure of the alloy. The microstructures for the water quenching (WQ) and oil quenching (OQ) specimens are composed of single α'' martensite phase, while for the air cooling (AC) specimen, the microstructure consists of predominant β phase and a small amount of fine athermal ω phase. During tensile deformation, two-stage yielding is observed in the alloy subjected to 800°C/0.5h/WQ heat treatment. The stress for martensite variants reorientation and the yield stress for plastic deformation are 310MPa and 455MPa, respectievely, and the maximum shape memory strain of 3.1% is obtained with pre-strain of 6%.

Superplasticity in Coarse-Grained Al-Mg Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 1285-1290 ◽  
Author(s):  
Ehab Samuel ◽  
John J. Jonas ◽  
F.H. Samuel ◽  
S.R. MacEwen
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Mg Alloys ◽  
Coarse Grained ◽  
High Temperature Deformation ◽  
Dynamic Strain ◽  
Temperature Deformation ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Al Mg Alloys

Superplasticity refers to a high temperature deformation process involving a marked sensitivity of the flow stress to the imposed strain rate, with resulting enhanced ductility. Although conventionally associated with fine-grained materials, superplasticity has recently been observed in coarse-grained alloys. The present research involves the deformation behavior of Al-Mg base alloys, where superpure Al-3%Mg and Al-5%Mg, and commercial Al 5056 were selected for study. The results for the Al-5%Mg and Al 5056 alloys are presented in this article. Flat sheet-type samples were tensile tested to 10% strain at increasing temperatures and at prescribed strain rates (0.001/s, 0.01/s, and 0.1/s). The dependence of flow stress on temperature was found to display some unusual characteristics. This behavior is interpreted as resulting from the occurrence of dynamic strain ageing (DSA). The aim of the overall study is to determine the relation between DSA and superplasticity in coarse-grained Al-Mg alloys. This will, in turn, lead to the control of the strain ageing behavior so as to produce the largest possible values of strain rate sensitivity (and, hence, elongation).

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