A study of the mechanism of hardness change of Al-Zn-Mg alloy during retrogression reaging treatments by small angle X-ray scattering (SAXS)
- Jilin Univ., Changchun (China). Materials Science Inst.
In this work, the changes in hardness of Al-Zn-Mg alloy during retrogression and reaging (RRA) treatments were detected and the mechanism of the hardness change was studied by Small Angle X-ray Scattering (SAXS). It was discovered that the hardness changes during RRA treatments are as follows. (1) Hardness decreases at the beginning of retrogression, achieves a minimum value at 90 seconds, and then increases and achieves the second maximum value at 6 minutes, and finally decreases simply. (2) Hardness of the reaged sample is higher than that of the retrogressed sample. The following conclusions were drawn from the experimental results of SAXS. (1) The drop in hardness for short retrogression time is attributed to the decrease of volume fraction of the precipitates and the growth of the particles; the drop in hardness with increasing retrogression time after the second maximum of hardness achieved is attributed to coarsening of the particles. (2) The increase in hardness during reaging is due to the occurrence of new precipitates and the increase of volume fraction of the precipitates.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 543481
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 28, Issue 10; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
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