scholarly journals Effect of severe plastic deformation by hydrostatic extrusion on the physical-mechanical properties of the U8A steel

Author(s):  
E. S. Gorkunov ◽  
S. M. Zadvorkin ◽  
L. S. Goruleva
2006 ◽  
Vol 114 ◽  
pp. 171-176 ◽  
Author(s):  
Joanna Zdunek ◽  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski

In this work, Al-Mg-Mn-Si alloy (5483) in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied 1.4, 2.8 and 3.8. All specimens were subjected to tensile tests and microhardness measurements. The investigated material revealed an instability during plastic deformation in the form of serration on the stress-strain curves, the so called Portevin-Le Chatelier effect It was shown that grain size reduction effected the character of the instability.


2006 ◽  
Vol 114 ◽  
pp. 145-150 ◽  
Author(s):  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Małgorzata Lewandowska ◽  
Wacław Pachla ◽  
Mariusz Kulczyk ◽  
...  

Hydrostatic extrusion can be viewed as one of the methods of Severe Plastic Deformation, SPD, for the fabrication of ultra-fine grained alloys which causes a significant increase in the mechanical properties such as tensile strength and hardness. In the present study the microstructure of 6082 aluminium alloy after hydrostatic extrusion was investigated. Hydroextrusion was performed in three steps with accumulated true strains of 1.34, 2.73 and 3.74 respectively. Microstructural observations were carried out using SEM, TEM and light microscopy. Grain and inclusion sizes, shapes and distribution were investigated in the HE processed samples. The study has shown that the hydrostatic extrusion process results in a profound refinement of both the grain size and the inclusions in 6082 aluminium alloy.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
D. Jakubowska ◽  
J. Zdunek ◽  
M. Kulczyk ◽  
J. Mizera ◽  
K. J. Kurzydłowski

The differences in the microstructure and texture of two Ni single crystals, with different initial orientations (100and110), and of polycrystalline nickel, before and after severe plastic deformation (SPD) produced by hydrostatic extrusion (HE), have been investigated. The crystals were deformed by a two-step HE process with a total deformation value ofε=1.2. The global texture, mechanical properties, and microstructure were examined after the deformation. In every investigated sample, the presence of111fibre texture was noted, while the starting orientation of a100Ni single crystal was preserved in 50% of the volume. The results obtained were compared with the relevant literature data.


The results on investigations of mechanical properties of high-purity titanium with grains ranging from tens of nanometers up to a few micrometers subjected to uniaxial tension, compression and microindenting are presented. Different structural states in high-purity titanium were formed by severe plastic deformation according to the scheme «upsetting – extrusion – drawing» in combination with annealing at temperatures of 250–550° C and quasi-hydrostatic extrusion at room and liquid nitrogen temperatures. The values of yield strengths and microhardness for samples of high-purity titanium with grains of different sizes are determined. It was shown that the combination of severe plastic deformation with cryogenic quasi-hydrostatic extrusion allowed to create high-purity nanocrystalline titanium with high mechanical properties. The obtained experimental data were analyzed for the implementation of the Hall-Petch relation and discrepancy between the values of yield strengths in tension and compression (strength differential or S-D effect). Satisfactory fulfillment of the Hall-Petch relation for high-purity titanium in the whole range of the studied grain size values was shown and a noticeable difference in the yield values for compression and tension was found. The values of the coefficients in the Hall-Petch equation for deformation by tension, compression and microindenting were determined. These coefficients are noticeably lower than the corresponding values for the industrial grades of titanium, i.e. in high-purity titanium, the grain boundaries are weaker barriers for moving dislocations than in the industrial titanium, whose boundaries are enriched with impurities. The features of the acoustic waves emission during compression of samples in various structural states were studied. It was concluded that the deformation of titanium in all the investigated structural states was carried out by dislocation slip.


2008 ◽  
Vol 140 ◽  
pp. 191-196 ◽  
Author(s):  
Krzysztof Topolski ◽  
Halina Garbacz ◽  
Wacław Pachla ◽  
Krzysztof Jan Kurzydlowski

Titanium was subjected to hydrostatic extrusion, a method of producing Severe Plastic Deformation (SPD). The experiments were aimed at refining the microstructure of the titanium in order to improve some of its mechanical properties. The effect of the initial state of titanium on the process of extrusion process and the final product was investigated. The results of these investigations are used to establish the optimum conditions for the hydrostatic extrusion process and more easily selecting the initial condition of the material according to the intended application of the extruded product.


2014 ◽  
Vol 59 (1) ◽  
pp. 59-64 ◽  
Author(s):  
M. Kulczyk ◽  
S. Przybysz ◽  
J. Skiba ◽  
W. Pachla

Abstract The study was concerned with the effect of severe deformation induced in one pass, by hydrostatic extrusion on the properties of fine aluminum, aluminum-silicon alloy, copper and silver wires. The influence of adiabatic heating which takes place during deformation on the mechanical properties and microstructure of the wires was examined. The quality of the surface of the wires was estimated. It has been demonstrated that fine aluminum and silver wires processed by hydrostatic extrusion have very good mechanical properties and a high-quality surface.


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):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3467
Author(s):  
Anna Nocivin ◽  
Doina Raducanu ◽  
Bogdan Vasile ◽  
Corneliu Trisca-Rusu ◽  
Elisabeta Mirela Cojocaru ◽  
...  

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.


2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.


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