In situ laser-ultrasonic monitoring of elastic parameters during natural aging in an Al-Zn-Mg-Cu alloy (AA7075) sheet

Watzl, Georg; Grünsteidl, Clemens; Arnoldt, Aurel; Nietsch, Jürgen A.; Österreicher, Johannes A.

doi:10.1016/j.mtla.2022.101600

Cited by 11 publications

(1 citation statement)

References 26 publications

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“…Grain sizing. and time-varying aspects such as growth, deformation, recovery, and recrystallization have been studied in a variety of metals, such as manganese alloys [5], cobalt alloys [21], nickel alloys [9,22], aluminum [19,23] and stainless steels [24][25][26][27]. Monitoring of the metallurgical composition is especially important in dual phase (or multiphase) steels, where formability and strength depend on the phase ratio and phase distribution [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Estimation of Grain Size and Composition in Steel Using Laser UltraSonics Simulations at Different Temperatures

Duijster

Volker²,

Berg³

et al. 2023

Applied Sciences

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The applicability of laser ultrasonics for the determination of grain size and phase composition in steels under different temperatures was investigated. This was done by obtaining the velocity and attenuation of propagating ultrasonic waves in a simulated steel medium. Samples of ferrite and austenite with varying microstructures were modelled and simulated with the finite difference method, as were samples with varying ratios of austenite and martensite. The temperature of the medium was taken into account as an essential parameter, since both velocity and attenuation are temperature dependent. Results of the velocity and attenuation analysis showed that the use of the wave propagation velocity is not feasible for determination of grain size or phase composition due to a high sensitivity to temperature and sample thickness. The frequency-dependent ultrasonic wave attenuation was less sensitive to the variation of temperature and sample thickness. It can be concluded that accurate knowledge of the temperature is essential for obtaining a correct grain size or phase ratio estimation: a temperature accuracy of 100 °C yields a grain size accuracy in the order of a micrometer using the attenuation. Similarly, a temperature accuracy of 70 °C leads to a phase ratio estimation accuracy of 10%.

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Section: Introductionmentioning

confidence: 99%

Estimation of Grain Size and Composition in Steel Using Laser UltraSonics Simulations at Different Temperatures

Duijster

Volker²,

Berg³

et al. 2023

Applied Sciences

View full text Add to dashboard Cite

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Differential scanning calorimetry of age-hardenable aluminium alloys: effects of sample preparation, experimental conditions, and baseline correction

Arnoldt,

Grohmann,

Strommer

et al. 2024

J Therm Anal Calorim

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Precipitation processes in age hardenable aluminium alloys are often investigated by differential scanning calorimetry (DSC). The endothermic and exothermic peaks of the DSC signal correspond to the dissolution and formation of phases, respectively. However, parasitic effects can lead to an unintended curvature of the DSC signal. Although a baseline correction can be used, some imperfections typically remain. Additionally, sample preparation and experimental conditions can influence the precipitation sequence itself and, therefore, the DSC curve. In this study, we investigate the influence of sample preparation by milling and punching on DSC curves for three different aluminium alloys: EN AW-2024, EN AW-6082, and EN AW-7075. Additionally, the influence of quenching and natural ageing was investigated for EN AW-6082. We found that deformation introduced by punching the DSC samples with a piercing die after heat treatment leads to a change in the precipitation kinetics in 2xxx, 6xxx, and 7xxx series alloys. The influence was strongest for punching the samples after solution heat treatment and less significant for punching after artificial ageing. The influence of sample preparation can be avoided by punching the samples before solution heat treatment. If this is not practicable, milling of the samples is a good alternative. The choice of quenching medium and short storage at room temperature before measurement (5 min) had only small effects on the DSC curves. Moreover, the start temperature of the measurement was found to be crucial. For observing phases forming below 100 °C and for low-bias baseline correction, the measurement should start at low-temperatures (i.e. $$\sim$$ ∼ − 50 °C).

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Comparative study of elastic properties measurement techniques during plastic deformation of aluminum, magnesium, and titanium alloys: application to springback simulation

Nietsch,

Ott,

Watzl

et al. 2024

Meccanica

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Reliable determination of the elastic moduli of metals can be quite demanding, especially as the apparent elastic modulus of metals is known to decrease with deformation. Traditionally, this dependence on plastic strain has been investigated through various tensile tests, but discrepancies persist across the different approaches. Here we compare several tensile test-based evaluation protocols based on loading-unloading experiments to measure the change in elastic moduli of the light metal alloys AZ31B, EN AW-6082, and Ti–6Al–4V during tensile deformation. Additionally, the initial Young’s modulus determination via tensile testing, three-point-bending experiments, contact-free laser ultrasonic zero-group-velocity plate resonance, and piezoelectric contact ultrasonic time-of-flight measurements were compared. The results reveal non-negligible differences in the strain-dependency of elastic moduli between the determination techniques. Additionally, the laser ultrasound measurements demonstrate an improved accuracy and repeatability for the determination of the initial elastic moduli of light metal sheets. The benefit of considering the reduction of the elastic moduli in finite element springback simulation of three-point-bending tests is demonstrated and the use of the chord modulus is found to be generally most appropriate.

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In situ laser-ultrasonic monitoring of elastic parameters during natural aging in an Al-Zn-Mg-Cu alloy (AA7075) sheet

Cited by 11 publications

References 26 publications

Estimation of Grain Size and Composition in Steel Using Laser UltraSonics Simulations at Different Temperatures

Estimation of Grain Size and Composition in Steel Using Laser UltraSonics Simulations at Different Temperatures

Differential scanning calorimetry of age-hardenable aluminium alloys: effects of sample preparation, experimental conditions, and baseline correction

Comparative study of elastic properties measurement techniques during plastic deformation of aluminum, magnesium, and titanium alloys: application to springback simulation

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