Peak microhardness recovery via T6 heat treatment with extremely soft annealed Al7075 feedstock in additive friction stir deposition

Autor: Huan Ding, Uttam Bhandari, Pengcheng Zhu, Ehsan Bagheri, Saeid Zavari, Yehong Chen, Yang Mu, Yongqiang Wang, Shengmin Guo
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Journal of Materials Research and Technology, Vol 32, Iss , Pp 2993-3003 (2024)
Druh dokumentu: article
ISSN: 2238-7854
DOI: 10.1016/j.jmrt.2024.08.132
Popis: With standard T6 heat treatments, precipitate-hardened alloys such as Al7075 and Al6061 fabricated using Additive Friction Stir Deposition (AFSD) method restore to noticeablely different peak mechanical properties. Previous research observed similar results but did not provide a viable solution. This study proposes a new processing strategy, namely enhanced plastic deformation by subjecting the Al7075 feedstock to annealed softening treatments. Specifically, by annealing the standard T651-Al7075 feedstock and deposition substrate (179 HV), their Microhardness were first degraded to its lowest state (80 HV), which is called a Soft-to-Soft system. For the Soft-to-Soft system subjected to AFSD, after undergoing appropriate T6 heat treatment, the microhardness of the AFSD 7075 alloy was restored to its peak value (183.1 ± 1.8 HV). The results indicate that this softening strategy can effectively reduce the non-strengthening phase in the AFSD matrix, thereby increasing the strengthening phase (η′ phase). This addresses the issue of traditional AFSD-prepared aluminum alloys being unable to achieve peak performance through T6 heat treatment.
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