Tensile and Fatigue Properties of Al-Mg-Sc-Zr Alloy Fine-Grained by Equal-Channel Angular Pressing

2013 ◽  
pp. 341-350 ◽  
Author(s):  
A. Washikita ◽  
K. Kitagawa ◽  
V.I. Kopylov ◽  
A. Vinogradov
2010 ◽  
Vol 667-669 ◽  
pp. 487-492
Author(s):  
Alla Kipelova ◽  
Ilya Nikulin ◽  
Sergey Malopheyev ◽  
Rustam Kaibyshev

Microstructural changes during equal channel angular pressing (ECAP) at the temperatures of 250 and 300°C to the strains ~4, ~8 and ~12 were studied in a coarse-grained Al-5.4%Mg-0.5%Mn-0.1%Zr alloy. At a strain of ~4, the microstructural evolution is mainly characterized by the development of well-defined subgrains within interiors of initial grains and the formation of fine grains along original boundaries. Further straining leads to increase in the average misorientation angle, the fraction of high-angle grain boundaries and the fraction of new grains. However, only at 300°C, the plastic deformation to a strain of ~12 leads to the formation of almost uniform submicrocrystalline (SMC) grained structure with an average crystallites size of ~ 0.5 m. At 250°C, the microstructure remains non-uniform and consists of subgrains and new recrystallized grains. The mechanism of new SMC structure formation after ECAP is discussed.


2016 ◽  
Vol 47 (12) ◽  
pp. 6056-6069 ◽  
Author(s):  
R. Alizadeh ◽  
R. Mahmudi ◽  
A. H. W. Ngan ◽  
P. H. R. Pereira ◽  
Y. Huang ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1191
Author(s):  
Ryuichi Yamada ◽  
Shoichiro Yoshihara ◽  
Yasumi Ito

A stent is employed to expand a narrowed tubular organ, such as a blood vessel. However, the persistent presence of a stainless steel stent yields several problems of late thrombosis, restenosis and chronic inflammation reactions. Biodegradable magnesium stents have been introduced to solve these problems. However, magnesium-based alloys suffer from poor ductility and lower than desired fatigue performance. There is still a huge demand for further research on new alloys and stent designs. Then, as fundamental research for this, AZ31 B magnesium alloy has been investigated for the effect of equal-channel angular pressing on the fatigue properties. ECAP was conducted for one pass and eight passes at 300 °C using a die with a channel angle of 90°. An annealed sample and ECAP sample of AZ31 B magnesium alloy were subjected to tensile and fatigue tests. As a result of the tensile test, strength in the ECAP (one pass) sample was higher than in the annealed sample. As a result of the fatigue test, at stress amplitude σa = 100 MPa, the number of cycles to failure was largest in the annealed sample, medium in the ECAP (one pass) sample and lowest in the ECAP (eight passes) sample. It was suggested that the small low cycle fatigue life of the ECAP (eight passes) sample is attributable to severe plastic deformation.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 654
Author(s):  
Ryosuke Matsutani ◽  
Nobuo Nakada ◽  
Susumu Onaka

Ultra-fine-grained (UFG) Cu shows little total elongation in tensile tests because simple shear deformation is concentrated in narrow regions during the initial stage of plastic deformation. Here, we attempted to improve the total elongation of UFG Cu obtained by equal-channel angular pressing. By making shallow dents on the side surfaces of the plate-like specimens, this induced pure shear deformation and increased their total elongation. During the tensile tests, we observed the overall and local deformation of the dented and undented UFG Cu specimens. Using three-dimensional digital image correlation, we found that the dented specimens showed suppression of thickness reduction and delay in fracture by enhancement of pure shear deformation. However, the dented and undented specimens had the same ultimate tensile strength. These results provide us a new concept to increase total elongation of UFG materials.


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