scholarly journals Gradients of Strain to Increase Strength and Ductility of Magnesium Alloys

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1028 ◽  
Author(s):  
Yao Liu ◽  
Songlin Cai
Keyword(s):  
Plastic Deformation ◽  
Magnesium Alloy ◽  
Density Gradient ◽  
Strain Gradient ◽  
Base Material ◽  
High Strength ◽  
Pure Torsion ◽  
Geometrically Necessary Dislocation ◽  
Inhomogeneous Microstructure ◽  
Strength And Ductility

A strain gradient was produced in an AZ31B magnesium alloy through a plastic deformation of pure torsion at a torsional speed of π/2 per second. Compared with the base material and with the alloy processed by conventional severe plastic deformation, the magnesium alloy provided with a strain gradient possesses high strength preserving its ductility. Microstructural observations show that strain gradient induces the formation of an inhomogeneous microstructure characterized by statistically stored dislocation (SSD) density gradient and geometrically necessary dislocation (GND). GNDs and dislocation density gradient provide extra strain hardening property, which contributes to the improvement of ductility. The combination of SSD density gradient and GND can simultaneously improve the strength and ductility of magnesium alloy.

Paradox of Strength and Ductility in Metals Processed Bysevere Plastic Deformation

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength ◽  
High Ductility ◽  
Elongation To Failure ◽  
Failure Ductility ◽  
Strength And Ductility

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.

Influence of Annealing on the Structure and Mechanical Properties of Ultrafine-Grained Alloy Ti-6Al-7Nb, Processed by Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 943-948 ◽  
Author(s):  
Veronika Polyakova ◽  
Irina P. Semenova ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Human Body ◽  
High Strength ◽  
Point Of View ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Strength And Ductility

This work is devoted to enhancement of strength and ductility of the Ti-6Al-7Nb ELI alloy, which is less harmful from medical point of view for human body in comparison to Ti-6Al-4V. It has been demonstrated that formation of an ultrafine-grained structure in the alloy with the help of equal-channel angular pressing in combination with heat and deformation treatments allows reaching high strength (UTS = 1400 MPa) and sufficient ductility (elongation 10 %).

Improvement of Mechanical Properties of Multiple Surface Rolled Pure Copper

2020 ◽  
Vol 311 ◽  
pp. 33-40
Author(s):  
Rui Wang ◽  
Dong Zhi Luo ◽  
Cheng Lu
Keyword(s):  
Plastic Deformation ◽  
Grain Boundaries ◽  
Pure Copper ◽  
High Strength ◽  
Microstructural Characterization ◽  
Sample Surface ◽  
Copper Sheet ◽  
Heterogeneous Distribution ◽  
Average Grain Size ◽  
Strength And Ductility

High strength can be achieved by severe plastic deformation but at the cost of ductility. A novel strategy, which named multiple surface rolling was applied on a homogeneous annealed pure copper to break the strength and ductility trade-off. A combination of high strength and acceptable ductility was achieved in copper strips after submitted to multiple surface rolling. The detail microstructure evolution rolled samples were characterized by EBSD observation and compared with the initially annealed ones. The average grain size does not show significant deviation in both initially annealed and multiple surfaces rolled copper. Detailed observations show a heterogeneous distribution of low angle grain boundaries through thickness direction. The low angle grain boundaries and misorientations revealed the potential strengthening mechanisms in the material. Both microstructural characterization and numerical simulations indicate that multiple surface rolling contributes to strain hardening at the sample surface, while the interior layer was undergoing elastic deformation or partial plastic deformation. This heterogeneous deformation renders copper sheet with a combination of high strength and ductility.

Experimental and Numerical Analysis on FSWed Magnesium Alloy Thin Sheets Obtained Using “Pin” and “Pinless” Tool

2012 ◽  
Vol 504-506 ◽  
pp. 747-752 ◽  
Author(s):  
Gianluca Buffa ◽  
Archimede Forcellese ◽  
Livan Fratini ◽  
Michela Simoncini
Keyword(s):  
Magnesium Alloy ◽  
Process Parameters ◽  
Material Flow ◽  
Base Material ◽  
Welding Process ◽  
Welding Parameters ◽  
Thin Sheets ◽  
Tool Geometries ◽  
Shoulder Diameter ◽  
Strength And Ductility

The present investigation aims at studying the effect of different tool geometries and process parameters on FSW of thin sheets in AZ31 magnesium alloy. In particular two properly designed tools, with shoulder diameters equal to 8 and 19 mm, were used; each of them was manufactured both in pin and pinless configurations. The effect of the different tool configurations and sizes, and welding parameters on mechanical properties of FSWed joints were analyzed in detail. The results were compared with those obtained on the base material. It was shown that FSWed joints are characterized by strength and ductility values lower than those of base material. Furthermore, the pin tool configuration, with a shoulder diameter of 8 mm, leads to the obtaining of strength and ductility values higher than those provided by the pinless one. A strong beneficial effect is obtained by increasing the shoulder diameter from 8 to 19 mm using the pinless configuration, whilst the FSW with the pin tool is critically affected by the welding conditions. The experimental work was joined to a numerical investigation based on finite element method (FEM) in order to study the material flow occurring during the welding process as well as the distribution of temperature, with the aim to identify a input window of the process parameters within which sound joints can be obtained.

scholarly journals Plastic deformation technology of high strength deformed magnesium alloy

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4137-4143
Author(s):  
Lu Xiao ◽  
Shutao Xiong
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Slip Surface ◽  
High Strength ◽  
Slip Direction ◽  
Average Grain Size ◽  
Cumulative Strain ◽  
Simulation Results

The traditional plastic deformation technology of magnesium alloys is relatively poor at high temperature, so a plastic deformation technology of high strength wrought magnesium alloys is designed. Firstly, the slip surface and slip direction which affect the properties of magnesium alloy are analyzed, then the rolling finite element is simulated, the simulation results are visualized, and the simulation information required by the user is output. The results show that the temperature rise decreases with the increase of initial deformation temperature, the average grain size decreases and the uniformity of grain size distribution increases gradually due to dynamic recrystallization, and the cumulative strain and strain distribution in the strain field increases gradually with each pass due to the existence of shear stress in the stress field.

A high strength and ductility Mg–Zn–Al–Cu–Mn magnesium alloy

2013 ◽  
Vol 47 ◽  
pp. 746-749 ◽  
Author(s):  
Jing Wang ◽  
Ruidong Liu ◽  
Tianjiao Luo ◽  
Yuansheng Yang
Keyword(s):  
Magnesium Alloy ◽  
High Strength ◽  
Strength And Ductility
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