Sürdürülebilir Kalkınma Amaçları

• 1

Yazarlar

• Demirtas, M.(2)
• Purcek, G.(2)
• Yanar, H.(2)
• Alemdag, Y.(1)
• Dobatkin, S.V.(1)
• Kawasaki, M.(1)
• Shangina, D.V.(1)

• MakaleYalnız künye2018Scopus SJRQ1/r/bayburt/12479
  High temperature superplasticity and deformation behavior of naturally aged Zn-Al alloys with different phase compositions

  Demirtas, M.; Kawasaki, M.; Yanar, H.; Purcek, G.

  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.

  AtıfScopus30·WoS30·OpenAlex33

  İncele
• MakaleYalnız künye2016Scopus SJRQ1/r/bayburt/13857
  Optimization of strength, ductility and electrical conductivity of Cu-Cr-Zr alloy by combining multi-route ECAP and aging

  Purcek, G.; Yanar, H.; Demirtas, M.; Alemdag, Y.; Shangina, D.V.; Dobatkin, S.V.

  Properties of Cu-Cr-Zr alloy with ultrafine-grained (UFG) structure produced by equal-channel angular pressing (ECAP) via different routes have been investigated. Special attention was paid to the optimization of multi-functional structural, thermal, electrical and mechanical properties of the alloy by aging of UFG one. Multi-pass ECAP via different routes gives rise to the formation of a deformation-induced submicrocrystalline structure with the grain (subgrain) sizes in the range of 200-300. nm depending on applied routes which leads to high hardness and strength in the Cu-Cr-Zr alloy with reduced ductility. Amongst the applied routes, route-Bc was found to be the best processing path for achieving the lowest grain size, the highest hardness and strength. Aging of 8Bc-processed UFG samples increases the hardness and strength of Cu-Cr-Zr alloy while retaining an electrical conductivity comparable to that of aged coarse-grained (CG) one. A satisfactory electrical conductivity of 71%IACS without considerable loss of peak hardness was achieved after aging of 8Bc-processed UFG alloy at 425. °C for 240. min. The precipitation strengthened UFG alloy remains its stable behavior at elevated temperatures up to 450. °C.

  • 
  AtıfScopus164·WoS147·OpenAlex151

  İncele