scholarly journals Influence of Grain Size and Texture on the Yield Strength of Mg Alloys Processed by Severe Plastic Deformation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jinbao Lin ◽  
Weijie Ren ◽  
Qudong Wang ◽  
Lifeng Ma ◽  
Yongjun Chen

Severe plastic deformation (SPD) has been widely employed to refine the grain size of Mg alloys, with the main objective to improve the strength and ductility of Mg alloys, since the well-known Hall-Petch equation suggests that a decreased grain size leads to an increased yield strength. However, the yield strength of Mg alloys processed by SPD is often decreased even though the grain size is effectively reduced. The abnormal flow behavior in Mg alloys processed by SPD has attracted great attention although this mechanism is still unclear, due to its complex and extensive influence factors. In this paper, the relationships between the processing conditions, grain refinement, and mechanical properties of the SPD treated Mg alloys are reviewed, with the emphasis on the effects of grain size and texture on the yield strength.

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe

It is well known that plastic deformation induced by conventional forming methodssuch as rolling, drawing or extrusion can significantly increase the strength of metalsHowever, this increase is usually accompanied by a loss of ductility. For example, Fig.1 shows that with increasing plastic deformation, the yield strength of Cu and Almonotonically increases while their elongation to failure (ductility) decreases. Thesame trend is also true for other metals and alloys. Here we report an extraordinarycombination of high strength and high ductility produced in metals subject to severeplastic deformation (SPD). We believe that this unusual mechanical behavior is causedby the unique nanostructures generated by SPD processing. The combination ofultrafine grain size and high-density dislocations appears to enable deformation by newmechanisms. This work demonstrates the possibility of tailoring the microstructures ofmetals and alloys by SPD to obtain both high strength and high ductility. Materialswith such desirable mechanical properties are very attractive for advanced structuralapplications.


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.


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 977 ◽  
Author(s):  
Xavier Sauvage ◽  
Xavier Quelennec ◽  
Peter Jessner ◽  
Florian Wetscher ◽  
Reinhard Pippan

AbstractGrain size reduction induced by severe plastic deformation (SPD) and the resulting mechanical properties have been widely investigated for pure metals but less is known and reported about multi-phase materials. To study the grain size reduction mechanisms in multiphase structure subjected to SPD, two copper based composites (Cu-10%Fe and Cu-43%Cr) were severely deformed by torsion under high pressure. The grain size achieved with these composite materials is much smaller than in pure metals. It is for example in a range of 10 to 20 nm for the Cu-43%Cr composite, e.g. one order of magnitude lower than in pure Cu processed by SPD. Three dimensional atom probe data show also the formation of non equilibrium supersaturated solid solutions. The mechanisms of the deformation induced intermixing are discussed together with its influence on the mechanical properties.


2020 ◽  
Vol 1003 ◽  
pp. 31-36
Author(s):  
Marko Vilotic ◽  
Li Hui Lang ◽  
Sergei Alexandrov ◽  
Dragisa Vilotic

Compared to conventional metal forming methods, processing by severe plastic deformation is mostly used to improve the mechanical properties and not for the shaping of a product. Processed material usually has an average crystal grain size of less than a micron and as a result, the material exhibits improvements in most of the mechanical properties, such as yield and ultimate tensile strength, microhardness, sufficiently high workability, good corrosion resistance, and implant biocompatibility and others. In this paper, a brief review of the processing by severe plastic deformation was presented, including the benefits, major methods, and the application. Additionally, a brief review of two methods made by authors was made.


2013 ◽  
Vol 48 (13) ◽  
pp. 4681-4688 ◽  
Author(s):  
Manping P. Liu ◽  
Hans J. Roven ◽  
Maxim Yu. Murashkin ◽  
Ruslan Z. Valiev ◽  
Ascar Kilmametov ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4176
Author(s):  
Shibo Zhou ◽  
Xiongjiangchuan He ◽  
Peng Peng ◽  
Tingting Liu ◽  
Guangmin Sheng ◽  
...  

The effect of Mn on the microstructure and mechanical properties of as-extruded Mg-0.5Sr alloy were discussed in this work. The results showed that high Mn alloying (2 wt.%) could significantly improve the mechanical properties of the alloys, namely, the tensile and compressive yield strength. The grain size of as-extruded Mg-0.5Sr alloys significantly was refined from 2.78 μm to 1.15 μm due to the pinning effect by fine α-Mn precipitates during the extrusion. Moreover, it also showed that the tensile yield strength and the compressive yield strength of Mg-0.5Sr-2Mn alloy were 32 and 40 percent age higher than those of Mg-0.5Sr alloy, respectively. Moreover, the strain hardening behaviors of the Mg-0.5Sr-2Mn alloy were discussed, which proved that a large number of small grains and texture have an important role in improving mechanical properties.


2010 ◽  
Vol 638-642 ◽  
pp. 1934-1939 ◽  
Author(s):  
Y.B. Chun ◽  
S.H. Ahn ◽  
D.H. Shin ◽  
S.K. Hwang

Recent advances in the severe plastic deformation technique have shown that effective refinement of the microstructure can be achieved in pure metals as well as in alloys. Among the various methods of severe plastic deformation, equal channel angular pressing has been the subject of numerous research works. Since the grain refining effect of this technique appears to reach a peak at a level of approximately 200 nm further microstructural changes are sought—deformation at a cryogenic temperature being one of the candidate routes. In the present study, we opted to combine equal channel angular pressing and low temperature plastic deformation to refine the microstructure of commercially pure V. The starting microstructure consisted of equiaxed grains with an average size of 100 micrometers. This microstructure was refined to a 200 nm thick lamellar microstructure by 8 passes of equal channel angular pressing at 350°C. The lamellar thickness was further reduced to 140 nm upon subsequent cryogenic rolling, which resulted in room temperature yield strength of 768 MPa. In the specimens, recrystallization annealed at 850°C, the grain size reached 1000 nm or larger, and the yield strength obeyed the Hall-Petch relationship with that grain size. The tensile elongation value, which was low and insensitive to the grain size in the as-deformed state, increased significantly up to 43% with the recrystallization annealing.


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