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.

Effect of Processing Parameters on Thermo-Mechanically Affected Zone of Friction Stir Processed AZ91 Magnesium Alloy

2010 ◽  
Author(s):  
M. Taherishargh ◽  
N. Parvin ◽  
P. Asadi
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Processing Parameters ◽  
The Other ◽  
Az91 Magnesium Alloy ◽  
Friction Stir ◽  
Az91 Magnesium

AZ91 Magnesium alloy was subjected to friction stir processing (FSP). The microstructural analyses of the friction stir processed (FSPed) specimens were carried out and the effects of pass number, rotational speed, and traverse speed upon thermo-mechanically affected zone (TMAZ) were investigated. The TMAZ is consisted of a region with highly elongated grains and a partially recrystalized zone. Decreasing the rotational speed and increasing the traverse speed increased the thickness of recrystallized zone; while, the thickness of the other zone decreased. On the other hand, it lessened the gradient of the grain size from the stir zone (SZ) to the base metal. Applying several FSP passes, lead to more homogeneous TMAZ structure with the finer grain size.

Microstructure and Corrosion Resistance of AZ80/Al Composite Plate Fabricated by Friction Stir Processing

2013 ◽  
Vol 747-748 ◽  
pp. 313-319 ◽  
Author(s):  
Fen Cheng Liu ◽  
Qiang Liu ◽  
Chun Ping Huang ◽  
Kun Yang ◽  
Cheng Gang Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Composite Plate ◽  
Composite Layer ◽  
Electrochemical Corrosion ◽  
Friction Stir ◽  
Alloy Substrate ◽  
Corrosion Medium ◽  
Al Composite

AZ80/Al composite plate was fabricated by means of friction stir processing (FSP) aimed at the improvement of corrosion resistance of magnesium alloy. The cross-section microstructure, surface morphology and corrosion resistance of the Al composite layer were investigated. The experiment results indicated that a dense composite Al layer with superfine and uniform grains was formed, and a few amount of intermetallic compounds existed in the area of Mg/Al interface. The bonding strength of AZ80 magnesium alloy substrate and 1060 pure Al layer was proved to be high which was resulted from the metallurgical bonding of FSP. Microhardness measurement showed the continuous changing of microhardness values from the outmost surface of composite Al layer to the magnesium alloy substrate. Results of electrochemical corrosion test of the composite plate in 5 wt.% NaCl solution showed the better protection effect of the composite Al layer on the magnesium alloy in a corrosion medium. Almost the same corrosion level on the whole corrosion surface was observed which indicated the highly uniform microstructure of the composite layer. It was also proved that the plain arches on the outmost surface of the composite Al layer had no influence on the corrosion resistance of composite Al layer.

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.

FABRICATION OF Mg/SiC NANOCOMPOSITE SURFACE LAYER USING FRICTION STIR PROCESSING TECHNIQUE

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1073-1076 ◽  
Author(s):  
YOONES ERFAN ◽  
SEYED FARSHID KASHANI-BOZORG
Keyword(s):  
Uniform Distribution ◽  
Friction Stir Processing ◽  
Composite Layer ◽  
Processing Technique ◽  
Speed Ratio ◽  
Friction Stir ◽  
Sic Particles ◽  
The Matrix ◽  
Tool Rotation

Friction stir processing (FSP) was employed to incorporate nano-sized SiC particles into the surface of AZ31 magnesium substrate in order to produce surface nanocomposite layers. Characterization of the microstructure of the processed layers exhibited powders agglomeration which was found to disperse with increasing the tool rotation speed/advancing speed ratio. A uniform distribution of SiC particles with a mean particle size of ~95 nm was achieved after second FSP passes. The matrix grain size was found to decrease by increasing the tool advancing speed and number of FSP passes; however, increasing the advancing speed resulted in introduction of defects which leads to tunnels. The micro hardness value of the composite layer with uniform distribution of nano-size SiC particles was found to be almost twice of that of the AZ31 substrate.

FABRICATION OF TI/SIC SURFACE NANO-COMPOSITE LAYER BY FRICTION STIR PROCESSING

2012 ◽  
Vol 05 ◽  
pp. 367-374 ◽  
Author(s):  
ALI SHAMSIPUR ◽  
SEYED FARSHID KASHANI-BOZORG ◽  
ABBAS ZAREIE-HANZAKI
Keyword(s):  
Friction Stir Processing ◽  
Composite Layer ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Commercially Pure Titanium ◽  
Nano Composite ◽  
Composite Surface ◽  
Friction Stir ◽  
Commercially Pure ◽  
Sic Particles

In the present investigation, novel Ti / SiC surface nano-composite layer was successfully fabricated by dispersing nano-sized SiC particles into commercially pure titanium plates employing friction stir processing technique. The process parameters such as tool rotation and advancing speeds were adjusted to produce defect-free surface composite layer, however, uniform distribution of the nano-size SiC particles in a matrix of titanium was achieved after the second pass. The micro hardness value of the Ti / SiC nano-composite surface layer was found to be ~534 HV; this is 3.3 times higher than that of the commercially pure titanium substrate. No reaction was detected between SiC powders and the titanium matrix after friction stir processing.

scholarly journals Microstructure, hardness and wear resistance of AZ91 magnesium alloy produced by friction stir processing with air cooling

2021 ◽  
Author(s):  
Józef Iwaszko ◽  
Krzysztof Kudła
Keyword(s):  
Wear Resistance ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
Vickers Hardness ◽  
Air Cooling ◽  
Az91 Magnesium Alloy ◽  
Friction Stir ◽  
Jet Cooling ◽  
Az91 Magnesium

Abstract Friction stir processing (FSP) was used to modify the surface layer of the AZ91 magnesium alloy. The treatment was carried out using a jet cooling nozzle, generating a stream of cold air and enabling intensive cooling of the friction stir processed (FSPed) zone. Single-pass FSP was carried out using a tool rotational speed of 500 rpm and travel speed of 30 mm/min. The treatment was conducted using a truncated cone-shaped tool with a threaded side surface. Strong grain refinement and microstructural changes typical for FSP were found in all the samples. Very fine, equiaxed recrystallized grains dominated in the stirring zone. In the samples modified with the jet cooling nozzle, greater grain refinement was obtained than in the case of naturally-cooled material. The average grain size in the surface part of the stirring zone was 1.4 µm and 9 µm in the samples with air cooling and with natural cooling, respectively. Both the naturally-cooled specimen and air-cooled specimen were characterized by a distinctly higher hardness than the base material. The average Vickers hardness in the stirring zone was 91 HV0.1 in the FSPed sample with the air-cooling system and 85.5 HV0.1 with natural cooling, respectively. The average Vickers hardness of the as-cast alloy was 64 HV0.1. Slightly higher wear resistance of the FSPed samples using a jet cooling nozzle was found in relation to the naturally-cooled sample. Based on the conducted research, high efficiency of the jet cooling nozzle in cooling the modified zone during friction stir processing was found.

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.

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