High temperature superplasticity and deformation behavior of naturally aged Zn-Al alloys with different phase compositions
Küçük Resim Yok
Tarih
2018
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Two Zn-Al alloys, eutectoid Zn-22Al and dilute Zn-0.3Al, were processed through equal-channel angular pressing (ECAP). The ECAP-processed alloys were subjected to long-term natural aging at room temperature for 120 days in order to investigate the effect of long-term natural aging on high-temperature superplasticity and the deformation behavior of these alloys. The grain size of the Zn-22Al alloy increased from 200 nm after ECAP to 400 nm after the natural aging process. The Zn-0.3Al alloy with a grain size of 1.3 µm after ECAP demonstrated a reasonably stable microstructure with the grain size of ~ 1.7 µm after long-term natural aging. The naturally aged ultrafine-grained (UFG) Zn-22Al alloy showed an excellent superplastic elongation of about 1800% at 200 °C. Grain boundary sliding was determined as the dominant deformation mechanism in this alloy. On the contrary, a considerably low elongation to failure of 230% was recorded in the naturally aged fine-grained (FG) Zn-0.3Al alloy at 150 °C, and dislocation creep was evaluated as the main deformation mechanism for this alloy. Detailed microstructural analyses showed that the FG Zn-0.3Al alloy was exposed to grain boundary corrosion during the natural aging process due to the presence of Al precipitates at grain boundaries whereas such formation was not observed in the UFG Zn-22% Al alloy. Grain boundary sliding was hindered by grain boundary corrosion and the cavity nucleation at the corroded grain boundaries caused a premature failure leading to such a low elongation in the Zn-0.3Al alloy. © 2018 Elsevier B.V.
Açıklama
Anahtar Kelimeler
Equal-channel angular pressing, Grain boundary corrosion, Natural aging, Superplasticity, Zn-Al alloys, Aluminum corrosion, Binary alloys, Creep, Elongation, Equal channel angular pressing, Grain boundary sliding, Grain size and shape, Pressing (forming), Superplasticity, Zinc alloys, Dominant deformation mechanism, Grain boundary corrosions, High-temperature superplasticities, Microstructural analysis, Natural aging, Superplastic elongation, Ultra-fine grained ( UFG), ZnAl alloy, Aluminum alloys, Equal-channel angular pressing, Grain boundary corrosion, Natural aging, Superplasticity, Zn-Al alloys, Aluminum corrosion, Binary alloys, Creep, Elongation, Equal channel angular pressing, Grain boundary sliding, Grain size and shape, Pressing (forming), Superplasticity, Zinc alloys, Dominant deformation mechanism, Grain boundary corrosions, High-temperature superplasticities, Microstructural analysis, Natural aging, Superplastic elongation, Ultra-fine grained ( UFG), ZnAl alloy, Aluminum alloys
Kaynak
Materials Science and Engineering A
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
730
