Severe plastic deformation induced nanocrystallization of melt-spun Al85Y8Ni5Co2 amorphous alloy

2008 ◽  
Vol 461 (1-2) ◽  
pp. 195-199 ◽  
Author(s):  
P. Henits ◽  
Á. Révész ◽  
A.P. Zhilyaev ◽  
Zs. Kovács
2006 ◽  
Vol 47 (3) ◽  
pp. 546-549 ◽  
Author(s):  
Vladimir G. Pushin ◽  
Ruslan Z. Valiev ◽  
Yuntian T. Zhu ◽  
Dmitrii V. Gunderov ◽  
Alexander V. Korolev ◽  
...  

2008 ◽  
Vol 584-586 ◽  
pp. 227-230 ◽  
Author(s):  
Alex M. Glezer ◽  
Sergey V. Dobatkin ◽  
Margarita R. Plotnikova ◽  
Anna V. Shalimova

The structure and mechanical properties of amorphous alloy Ni44Fe29Co15Si2B10 after severe plastic deformation (SPD) in Bridgman chamber at the different temperatures (77 and 298 K) have been studied. It is shown that the early stages of the SPD of amorphous alloy cause a noticeable decrease in microhardness HV and significant changes in the physical properties. With increasing the value of SPD the transition from inhomogeneous to homogeneous (or to qualitatively different) mode of plastic flow is observed, which is accompanied by the effects of homogeneous nanocrystallization. The nanoparticle size does not exceed 10 nm. It is established that the thermally activated nanocrystallization processes can occur at very low temperatures (77 K).


2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.


Author(s):  
Андрей Дмитриевич Бухтеев ◽  
Виктория Буянтуевна Бальжиева ◽  
Анна Романовна Тарасова ◽  
Фидан Гасанова ◽  
Светлана Викторовна Агасиева

В данной статье рассматривается применение и технологии получения наноструктурированных поверхностей. Рассмотрены такие методы как компактирование порошков (изостатическое прессование, метод Гляйтера), интенсивная пластическая деформация (угловое кручение, равноканальное угловое прессование, обработка давлением многослойных композитов) и модификация поверхности (лазерная обработка, ионная бомбардировка). This article discusses the application and technology for obtaining nano-structured surfaces. Methods such as compaction of powders (isostatic pressing, Gleiter method), severe plastic deformation (angular torsion, equal-channel angular pressing, pressure treatment of multilayer composites) and surface modification (laser treatment, ion bombardment) are considered.


2007 ◽  
Vol 345-346 ◽  
pp. 45-48 ◽  
Author(s):  
Jozef Zrník ◽  
Sergey V. Dobatkin ◽  
Ondrej Stejskal

The article focuses on the results from recent experimental of severe plastic deformation of low carbon (LC) steel and medium carbon (MC) steel performed at increased temperatures. The grain refinement of ferrite respectively ferrite-pearlite structure is described. While LC steel was deformed by ECAP die (ε = 3) with a channel angle φ = 90° the ECAP severe deformation of MC steel was conducted with die channel angle of 120° (ε = 2.6 - 4). The high straining in LC steel resulted in extensively elongated ferrite grains with dense dislocation network and randomly recovered and polygonized structure was observed. The small period of work hardening appeared at tensile deformation. On the other side, the warm ECAP deformation of MC steel in dependence of increased effective strain resulted in more progressive recovery process. In interior of the elongated ferrite grains the subgrain structure prevails with dislocation network. As straining increases the dynamic polygonization and recrystallization became active to form mixture of polygonized subgrain and submicrocrystalline structure. The straining and moderate ECAP temperature caused the cementite lamellae fragmentation and spheroidzation as number of passes increased. The tensile behaviour of the both steels was characterized by strength increase however the absence of strain hardening was found at low carbon steel. The favourable effect of ferrite-pearlite structure modification due straining was reason for extended work hardening period observed at MC steel.


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