Strain Rate Dependence of Material Strength in AA5xxx Series Aluminum Alloys and Evaluation of Their Constitutive Equation

Abstract

The effect of strain rate on the mechanical properties of AA5xxx series aluminum alloys containing solute Mg atoms (AA5005, AA5021, AA5082 and AA5182) and pure aluminum (A1070) was investigated within a wide strain rate range of 1.0 × 10−4 to 1.0 × 103 s−1 at room temperature. The A1070 exhibited a positive strain rate dependence of material strength at the investigated strain rates. However, the AA5xxx series aluminum alloys primarily exhibited the negative strain rate dependence of material strength and serration caused by the Portevin-Le Chatelier effect on the Mg content and strain rate. As a result of using the material constitutive equation for the negative strain rate dependence, it was found that the flow stress may change in the dynamic strain rate range. However, it was found that the strain rate dependence of material strength differed in the AA5082 and the AA5182 alloys. It would be caused by less solute Mg of the Al phase in the AA5182 alloy than in the AA5082 alloy, because more Mg2Si compounds precipitated on Mn bearing particles as precipitation sites in the AA5182 alloy.

Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

“…At quasi-static rates of strain, obvious serrations in the curves are visible. These are presumably due to the Portevin-Le-Chatelier (PLC) effect, which describes the locking of a moving dislocation due to solute Mg atoms [13]. At higher strain rates, this effect diminishes as the diffusion speed of solute Mg becomes slow compared to the dislocation speed.…”

“…Our work provides the necessary data and a model to design and simulate such structures, including the effects of strain rate. On the other hand, from a more scientific point of view, it is interesting to see how different strain rate effects of Sc and Mg combine in one aluminium alloy: for moderate strain rates <≈ 10 3 , the addition of Mg mainly leads to negative strain-rate sensitivity [13], while the addition of Sc incurs a pronounced positive strain rate sensitivity [15] for the UTS. For Scalmalloy, with alloying values of 4.4% Mg and 0.73% Sc by weight [10], these effects appear to mutually cancel out.…”

“…Al-Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates [12]. In contrast, Al-Mg alloys are known to show the contrary effect, they exhibit negative strain rate sensitivity, at least up to moderate strain rates of 10 3 /s [13]. To answer the question how these effects combine in AA5028, we study its dynamic behaviour at four different strain rates ranging from 10 −3 to 1000 /s using servo-hydraulic and split-Hopkinson testing methods.…”

Dynamic Behavior of Self-Piercing Riveted and Mechanical Clinched Joints of Dissimilar Materials: An Experimental Comparative Investigation

“…e substrate materials have different responses to the strain rate effect. Previous studies have reported that a negative strain rate dependence of the material strength has been observed for Al-Mg alloys at a quasistatic strain rate, but there is a positive strain rate dependence for a high strain rate [19]. e yielding strain rate of DX51D+Z could increase by approximately 50% from static to intermediate strain rates [20].…”

Review of Intermediate Strain Rate Testing Devices

“…Many researchers have carried out the experimental tests at various strain rate conditions and found that the material exhibits an increased yield strength and flow stress with increased strain rate [6][7][8][9][10][11][12], the existing material models developed by the researchers cannot predict, very accurately, the microstructure changes that are taking place during the manufacturing processes [13,14]. During heat deformation, the material undergoes dynamic strain-hardening and dynamic softening (consisting of dynamic recovery (DRV) and dynamic recrystallization (DRX)), resulting in the evolution of the complex microstructure of the deformed material which is directly reflected in the flow stress curves [15].…”