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.

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.

Material flow modeling for the DSFSW of magnesium alloy

2020 ◽  
pp. 030932472097661
Author(s):  
Parviz Asadi ◽  
MohammadHosein Mirzaei
Keyword(s):  
Magnesium Alloy ◽  
Rotational Speed ◽  
Material Flow ◽  
Sheet Thickness ◽  
Maximum Temperature ◽  
Flow Modeling ◽  
Az91 Magnesium Alloy ◽  
Friction Stir ◽  
Az91 Magnesium ◽  
Tool Pin

The Coupled Eulerian Lagrangian (CEL) method is utilized to model the double shoulder friction stir welding (DSFSW) of AZ91 magnesium alloy and then the model is verified by the experiments. The effects of tool rotational speed and sheet thickness on temperature and strain distributions as well as the material flow patterns are considered at different steps of the process. The material flow pattern around the tool pin is demonstrated properly and the shoulder driven and pin driven zones are predicted very well. Results show that, the material movement in shoulder driven and pin driven zones is different, while it is from the advancing side (AS) to the retreating side (RS) in the pin driven zone, it is inverse in the shoulder driven zone. Additionally, increase in rotational speed raises the maximum temperature and strain, improves the material movement, expands the SZ width and increases the depth of shoulder driven zone. Furthermore, increase in sheet thickness results in a decrease in maximum temperature and strain as well as the material movement. In the sheets with low thickness due to the effects of two shoulders, the pin driven zone is not distinguishable, however in thicker welding sheets the pin driven zone is obvious by significantly lower strains.

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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