NUMERICAL SIMULATION OF FRICTION STIR BUTT WELDING PROCESSES FOR AZ91 MAGNESIUM ALLOY

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.

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Microstructural simulation of friction stir welding using a cellular automaton method: a microstructure prediction of AZ91 magnesium alloy

International Journal of Mechanical and Materials Engineering ◽

10.1186/s40712-015-0048-5 ◽

2015 ◽

Vol 10 (1) ◽

Cited By ~ 16

Author(s):

Parviz Asadi ◽

Mohammad Kazem Besharati Givi ◽

Mostafa Akbari

Keyword(s):

Friction Stir Welding ◽

Magnesium Alloy ◽

Cellular Automaton ◽

Az91 Magnesium Alloy ◽

Friction Stir ◽

Microstructure Prediction ◽

Az91 Magnesium ◽

Cellular Automaton Method

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Microstructures and tensile properties of submerged friction stir processed AZ91 magnesium alloy

Journal of Magnesium and Alloys ◽

10.1016/j.jma.2015.08.001 ◽

2015 ◽

Vol 3 (3) ◽

pp. 203-209 ◽

Cited By ~ 28

Author(s):

Fang Chai ◽

Datong Zhang ◽

Yuanyuan Li

Keyword(s):

Magnesium Alloy ◽

Tensile Properties ◽

Az91 Magnesium Alloy ◽

Friction Stir ◽

Az91 Magnesium

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

10.21203/rs.3.rs-187500/v1 ◽

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.

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