Speaker
Description
Recent developments in high temperature nanoindentation have opened the way to investigate Young’s modulus [1], hardness and creep properties [2] at very high temperature (up to 1100°C). In the meantime, Baral et al.[3] carried out in situ nanoindentation measurements at high temperature to characterize the recrystallization kinetics of a cold-rolled aluminum during annealing at 300°C. However, before being able to conduct tests at high temperature, time-consuming heating and stabilization steps have to be carried-out. Therefore, important information about early material’s transformation could be lost.
A new methodology, named High Temperature Scanning Indentation [4], has been developed to overcome issues of high temperature nanoindentation testing. It is based on a high-speed indentation cycle which lasts 1 second to minimize thermal drift issues. The idea is to linearly ramp the system in temperature and to applied multiple high-speed indentation cycles at the same time. This technique allows quasi-continuous determination of Young’s modulus, hardness and creep properties versus temperature in a more efficient way than previous methods. It was validated on fused silica and pure aluminum up to 325°C.
This new methodology has been applied on cold-rolled pure aluminum that undergoes microstructural changes during a thermal ramp. The variations of hardness against temperature upon heating and cooling point out the occurrence of static recovery when heating. Moreover, the drop of hardness at high-temperature is related to recrystallization. Those results were assessed using post-mortem Electron Back-Scattering Diffraction measurements.
[1] C. Minnert et al., Materials & Design, 192, 108727, 2020
[2] P. S. Phani et al. Acta Materialia, 111, 31–38, 2016
[3] P. Baral et al. Materials & Design, 152, 22–29, 2018
[4] G. Tiphéne et al., Journal of Material Research, accepted for publication
| Speaker Country | France |
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