Optimization of Retrogression Parameters of AA7010 Alloy
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The present work has been carried out on an AA7010 aluminium alloy so as to optimize the retrogression and re-aging (RRA) schedule that leads to the optimal combination of mechanical properties and stress corrosion cracking (SCC) resistance. The alloy is heat treated at different retrogression temperatures for varying retrogression time and subsequently the window for optimization of retrogression parameters of RRA schedule is established after re-aging. It is found that retrogression at 473 K for 35 min results into the best combination of the above properties. The enhancement in mechanical properties and SCC resistance is due to the formation of discontinuous and coarse precipitates along the grain boundaries and also the copper enrichment of the precipitates that occur during optimum RRA schedule. It is established that proper control of the process parameters is essential to control the final microstructure and thereby enhance the mechanical properties and SCC resistance of the alloys.
KeywordsRetrogression Re-aging (RRA) SCC resistance Peak aging Electrical conductivity SEM TEM
The authors are pleased to acknowledge financial support for this research from Defence Research and Development Organization (DRDO)—Naval Research Board, Government of India, and Aeronautical Development Agency (ADA) for its cooperation.
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