In situ DSC investigation into the kinetics and microstructure of dispersoid formation in Al-Mn-Fe-Si(-Mg) alloys

Kemsies, Richard H.; Milkereit, Benjamin; Wenner, Sigurd; Holmestad, Randi; Keßler, Olaf

doi:10.1016/j.matdes.2018.03.007

Cited by 37 publications

(25 citation statements)

References 23 publications

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“…Similar cases with increasing areas of the dissolution peaks at higher heating rates can be found in multiple cases of different age-hardening Al alloys and different initial heat treatment states [120,127,144,149]. One likely reason for the more severe suppression of precipitation compared to dissolution is the different diffusion distances of these reactions.…”

Section: Capabilities and Limitations Of Dsc Heating Curve Analysis Asupporting

confidence: 62%

“…This may be caused by slight differences in the sample position for each individual measurement, for instance [125]. Thus, the raw DSC data must undergo a sophisticated data treatment prior to evaluation, including baseline subtraction in each case, and possibly also the elimination of the remaining zero-level curvature [120] or a mean value curve calculation [122,123,127]. If efforts are made to ensure the best zero level quality, a result that is straight and close to zero can be achieved.…”

Section: Zero-level Accuracymentioning

confidence: 99%

“…The course of the DSC heating curve strongly depends on the initial state of the sample and the heating rate, e.g., Ref. [75,117,120,127,144,[157][158][159][160]. The differences from the initial state are therefore mostly relevant at temperatures below about 300 • C (see Figure 18, which shows heating DSC curves for three AlMgSi alloys in different initial heat treatment states).…”

Section: A T 1 B T4mentioning

confidence: 99%

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Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation

et al. 2019

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For aluminium alloys, precipitation strengthening is controlled by age-hardening heat treatments, including solution treatment, quenching, and ageing. In terms of technological applications, quenching is considered a critical step, because detrimental quench-induced precipitation must be avoided to exploit the full age-hardening potential of the alloy. The alloy therefore needs to be quenched faster than a critical cooling rate, but slow enough to avoid undesired distortion and residual stresses. These contrary requirements for quenching can only be aligned based on detailed knowledge of the kinetics of quench-induced precipitation. Until the beginning of the 21st century, the kinetics of relevant solid-solid phase transformations in aluminium alloys could only be estimated by ex-situ testing of different properties. Over the past ten years, significant progress has been achieved in this field of materials science, enabled by the development of highly sensitive differential scanning calorimetry (DSC) techniques. This review presents a comprehensive report on the solid-solid phase transformation kinetics in Al alloys covering precipitation and dissolution reactions during heating from different initial states, dissolution during solution annealing and to a vast extent quench-induced precipitation during continuous cooling over a dynamic cooling rate range of ten orders of magnitude. The kinetic analyses are complemented by sophisticated micro- and nano-structural analyses and continuous cooling precipitation (CCP) diagrams are derived. The measurement of enthalpies released by quench-induced precipitation as a function of the cooling rate also enables predictions of the quench sensitivities of Al alloys using physically-based models. Various alloys are compared, and general aspects of quench-induced precipitation in Al alloys are derived.

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Section: Capabilities and Limitations Of Dsc Heating Curve Analysis Asupporting

confidence: 62%

Section: Zero-level Accuracymentioning

confidence: 99%

Section: A T 1 B T4mentioning

confidence: 99%

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Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation

et al. 2019

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“…Experiment specific curve fluctuations (e.g., caused by slight position differences of the sensor-lid or sample [17]) are definitely minimized by averaging the curves measured for a single set of parameters. This data treatment was recently introduced by our group, and discussed in detail in Kemsies et al [18]. As the reproducibility of the DSC measurements was found to be high, with small fluctuations, as shown in Figure 1D, we do not plot the curve fluctuation ranges here to maximize the readability of the plots, which also allows for the easy comparison of multiple DSC curves.…”

Section: Q S Andmentioning

confidence: 99%

Influence of Solution-Annealing Parameters on the Continuous Cooling Precipitation of Aluminum Alloy 6082

Fröck

Milkereit

Wiechmann

et al. 2018

Metals

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Abstract:We use a systematic approach to investigate the influence of the specific solution condition on quench-induced precipitation of coarse secondary phase particles during subsequent cooling for a wide range of cooling rates. Commercially produced plate material of aluminum alloy EN AW-6082 was investigated and the applied solution treatment conditions were chosen based on heating differential scanning calorimetry experiments of the initial T651 condition. The kinetics of the quench-induced precipitation were investigated by in situ cooling differential scanning calorimetry for a wide range of cooling rates. The nature of those quench-induced precipitates was analyzed by electron microscopy. The experimental data was evaluated with respect to the detrimental effect of incomplete dissolution on the age-hardening potential. We show that if the chosen solution temperature and soaking duration are too low or short, the solution treatment results in an incomplete dissolution of secondary phase particles. This involves precipitation during subsequent cooling to start concurrently with the onset of cooling, which increases the quench sensitivity. However, if the solution conditions allow the formation of a complete solid solution, precipitation will start after a certain degree of undercooling, thus keeping the upper critical cooling rate at the usual alloy-specific level.

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“…Pure aluminum (99.9995%) with the same dimensions as the samples was used as reference material. The evaluation of DSC heating experiments was done according to the method proposed by Kemsies et al [34]. At least three individual samples for each initial condition were investigated.…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

On the long-term aging of S-phase in aluminum alloy 2618A

et al. 2021

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The aluminum alloy 2618A is applied for engine components such as radial compressor wheels which operate for long time at elevated temperatures. This results in coarsening of the hardening precipitates and degradation in mechanical properties during the long-term operation, which is not taken into account in the current lifetime prediction models due to the lack of quantitative microstructural and mechanical data. To address this issue, a quantitative investigation on the evolution of precipitates during long-term aging at 190 °C for up to 25,000 h was conducted. Detailed transmission electron microscopy (TEM) was combined with Brinell hardness measurements and thorough differential scanning calorimetry (DSC) experiments. The results show that GPB zones and S-phase Al2CuMg grow up to < 1,000 h during which the GPB zones dissolve and S-phase precipitates form. For longer aging times, only S-phase precipitates coarsen, which can be well described using the Lifshitz–Slyozov–Wagner theory of ripening. A thorough understanding of the underlying microstructural processes is a prerequisite to enable the integration of aging behavior into the established lifetime models for components manufactured from alloy 2618A.

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In situ DSC investigation into the kinetics and microstructure of dispersoid formation in Al-Mn-Fe-Si(-Mg) alloys

Cited by 37 publications

References 23 publications

Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation

Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation

Influence of Solution-Annealing Parameters on the Continuous Cooling Precipitation of Aluminum Alloy 6082

On the long-term aging of S-phase in aluminum alloy 2618A

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