Microstructure and Low-Temperature Superplasticity of Fine-Grain ZK60 Magnesium Alloy Produced by Equal-Channel Angular Pressing

2015 ◽  
Vol 4 (6) ◽  
pp. 518-524 ◽  
Author(s):  
Yandong Yu ◽  
Shuzhen Kuang ◽  
Desheng Chu ◽  
Hao Zhou ◽  
Jie Li ◽  
...  
2005 ◽  
Vol 488-489 ◽  
pp. 581-584 ◽  
Author(s):  
Li Lin ◽  
Li Jia Chen ◽  
Zhen Liu

Microstructure evolution and superplastic behaviors of ZK40 magnesium alloy were investigated in the temperature range of 473 ~ 623 K. Twinning occurred significantly after being processed by equal channel angular pressing (ECAP) for one pass through the die, the mean grain size was 5.6 µm. Finer grains can be obtained after further processing through ECAP, the average grain size of the alloy processed by ECAP for three passes was as low as 0.8 µm; this alloy exhibited low temperature superplasticity at 473 ~ 523 K, elongations at an initial strain rate of 1×10-3 s-1 were 260 % at 473 K and 612 % at 523 K, respectively. The incompatibility between fine and coarse grains was thought to be unfavorable to the improvement of superplasticity. Low temperature superplasticity of the as-ECAP ZK40 alloy can be attributed to the relatively finer grain size and the homogeneity of microstructure.


2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Przemysław Snopiński ◽  
Mariusz Król ◽  
Marek Pagáč ◽  
Jana Petrů ◽  
Jiří Hajnyš ◽  
...  

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.


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.


2014 ◽  
Vol 609-610 ◽  
pp. 495-499
Author(s):  
Guo Cheng Ren ◽  
Xiao Juan Lin ◽  
Shu Bo Xu

The microstructure and material properties of AZ31 magnesium alloy are very sensitive to process parameters, which directly determine the service properties. To explore and understand the deformation behavior and the optimization of the deformation process, the microstructure evolution during equal channel angular pressing was predicted by using the DEFORM-3D software package at different temperature. To verify the finite element simulation results, the microstructure across the transverse direction of the billet was measured. The results show that the effects strain and deformation temperatures on the microstructure evolution of AZ31 magnesium during ECAP process are significant, and a good agreement between the predicted and experimental results was obtained, which confirmed that the derived dynamic recrystallization mathematical models can be successfully incorporated into the finite element model to predict the microstructure evolution of ECAP process for AZ31 magnesium.


2013 ◽  
Vol 803 ◽  
pp. 226-229
Author(s):  
Da Ran Fang ◽  
Chun Liu ◽  
Feng Fang Liu

Al-3.9wt.%Cu alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy increases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the alloy subjected to ECAP can be improved by relief annealing.


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