scholarly journals Friction Stir Processing of the Magnesium Alloy AZ61: Grain Size Refinement and Mechanical Properties

2012 ◽  
Vol 706-709 ◽  
pp. 1823-1828 ◽  
Author(s):  
J.A. del Valle ◽  
P. Rey ◽  
D. Gesto ◽  
D. Verdera ◽  
Oscar A. Ruano
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Superplastic Forming ◽  
Important Change ◽  
Heat Extraction ◽  
Processing Temperature ◽  
Friction Stir ◽  
Size Refinement

The effect of friction stir processing (FSP), on the microstructure and mechanical properties of a magnesium alloy AZ61 has been analyzed. This is a widely used wrought magnesium alloy provided in the form of rolled and annealed sheets with a grain size of 45 μm. The FSP was performed with an adequate cooling device in order to increase the heat extraction and reduce the processing temperature. The final microstructure showed a noticeable grain size refinement down to values close to 1.8 μm and an important change in texture. The change in texture favors basal slip during tensile testing leading to an increase of ductility and a decrease in yield stress. The stability of the grain size and the creep behavior at high temperatures were investigated. The optimum conditions for superplastic forming were determined; however, the presence of a large amount of cavities precludes the achievement of high superplastic elongations. Additionally, these results are compared with those obtained by severe hot rolling.

Surface Modification of Pure Magnesium and Magnesium Alloy AZ91 by Friction Stir Processing

2015 ◽  
Vol 651-653 ◽  
pp. 796-801 ◽  
Author(s):  
Andreas Hütter ◽  
Wilfried Huemer ◽  
Claudia Ramskogler ◽  
Fernando Warchomicka ◽  
Aymen Lachehab ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Friction Stir Processing ◽  
Phase Distribution ◽  
Intermetallic Phases ◽  
Friction Stir ◽  
Alloy Az91 ◽  
Magnesium Alloy Az91

In recent years an interest in magnesium and magnesium alloys not only for the automotive industry but also for medical applications was increasing due to the low density and good specific strength. Magnesium alloys show good castability but lower ductility and strength than wrought materials. For this reason, refinement of grains and homogenous distribution of intermetallic phases are needed to improve formability and mechanical properties. On the other hand, the degradation of the material by corrosion is influenced by the grain size and phase distribution. This work investigates the microstructure evolution of pure Mg and magnesium alloy AZ91 by friction stir processing (FSP) technique. FSP experiments are carried out by constant force, optimizing the rotation and feed rate to obtain a homogenous microstructure, free of defects stir zone, good surface finishing and stable conditions during the process. The results show that the grain size is affected by the spindle speed. Increasing the number of passes reduces also the size of the grains and the intermetallic phases in the AZ91 alloy. The overlapping of passes between overlapping ratio 0.5 to 1 determines an uniform depth of the stir zone over a larger surface area.Hardness measurements are performed to evaluate the influence of FSP parameters on the mechanical properties. The degradation rate of the studied FSP Mg alloys is determined by hydrogen evolution in corrosion immersion tests, which depend strongly on the phase distribution and grain size.

PRODUCING NANOCOMPOSITE LAYER ON THE SURFACE OF AS-CAST AZ91 MAGNESIUM ALLOY BY FRICTION STIR PROCESSING

2012 ◽  
Vol 05 ◽  
pp. 375-382
Author(s):  
P. ASADI ◽  
M. K. BESHARATI GIVI ◽  
G. FARAJI
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Composite Layer ◽  
Az91 Magnesium Alloy ◽  
Friction Stir ◽  
Nanocomposite Layer ◽  
Sic Particles ◽  
Developed Surface ◽  
Mechanical And Microstructural Properties

Friction stir processing (FSP) is an effective tool to produce a surface composite layer with enhanced mechanical properties and modified microstructure of as-cast and sheet metals. In the present work, the mechanical and microstructural properties of as-cast AZ 91 magnesium alloy were enhanced by FSP and an AZ 91/ SiC surface nanocomposite layer has been produced using 30 nm SiC particles. Effect of the FSP pass number on the microstructure, grain size, microhardness, and powder distributing pattern of the surface developed has been investigated. The developed surface nanocomposite layer presents a higher hardness, an ultra fine grain size and a better homogeneity. Results show that, increasing the number of FSP passes enhances distribution of nano-sized SiC particles in the AZ 91 matrix, decreases the grain size, and increases the hardness significantly. Also, changing of the tool rotating direction results much uniform distribution of the SiC particles, finer grains, and a little higher hardness.

Enhancing the Mechanical Properties of AE42 Magnesium Alloy through Friction Stir Processing

2013 ◽  
Vol 16 (5) ◽  
pp. 571-580 ◽  
Author(s):  
Harpreet Singh Arora ◽  
Harpreet Singh Grewal ◽  
Harpreet Singh ◽  
Brij Kumar Dhindaw ◽  
Sundeep Mukherjee
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Friction Stir

scholarly journals Effect of friction stir processing parameters on the microstructure and properties of ZK60 magnesium alloy

2021 ◽  
Author(s):  
Yijie Hu ◽  
Youping Sun ◽  
Jiangmei He ◽  
Dejun Fang ◽  
Jiaxin Zhu ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Boundaries ◽  
Friction Stir Processing ◽  
Processing Speed ◽  
Rotation Speed ◽  
Processing Parameters ◽  
High Angle ◽  
Friction Stir ◽  
Zk60 Magnesium Alloy

Abstract Friction stir processing is an important method for acquiring ultrafine-grained materials. In this paper, 3mm ZK60 magnesium alloy sheet was carried for friction stir processing. The best processing parameters with a small grain size and maximum mechanical properties were obtained by comparing different rotation speeds and processing speeds. Fine recrystallized grains and high-angle grain boundaries were observed in stirring zone under different processing parameters. With increasing rotation speed, the grain size and high-angle grain boundary ratio increase; while with increasing processing speed, the grain size decrease, and the ratio of high-angle grain boundaries increase. When rotation speed and processing speed are 1400 r·min-1 and 100 mm·min-1, the processing plate have the largest ultimate tensile strength are 267.52 Mpa, that reached 84.62% of the base metals, and the yield strength, elongation and grain size are 166.97 Mpa, 15.32 % and 1.12 ± 1.64 µm, respectively. The processing plate has more excellent damping performance than rolled.

Effect of Distance between Passes in Friction Stir Processing of Magnesium Alloy

2012 ◽  
Vol 585 ◽  
pp. 397-401 ◽  
Author(s):  
M. Govindaraju ◽  
K. Rao Prasad ◽  
Uday Chakkingal ◽  
K. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Developmental Studies ◽  
Secondary Phases ◽  
Friction Stir ◽  
Processed Material ◽  
The Matrix ◽  
Cast Alloys ◽  
Tool Pin

Friction stir processing is applied for property improvement of cast alloys for last two decades and many developmental studies were carried out in this topic on various alloys. In the current work, friction stir processing was carried out on rare earth containing magnesium alloy AE42. This alloy was specially developed for automobile application as it has better creep resistance than commercial magnesium alloys. Multi-pass Friction Stir Processing was carried out with varying the distance between passes from 0.5 mm to 2.5 mm using 12 mm shoulder diameter tool. Pin was with conical (tapered) and flat configurations with 3 mm height. After processing, the resultant mechanical and metallurgical properties were evaluated. Microstructure was refined to 5 micron and the secondary phases were made in to tiny pieces of 0.5-1 micron and evenly distributed in the matrix. Continuous network of grain boundary which is reason for poor mechanical properties was eliminated. Mechanical properties were improved by 30%. The variation of mechanical properties of processed material with respect to variation of distance between passes was negligible from 1 mm to 1.5 mm for flat pin tool.

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