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The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys

Doctor of Philosophy in Materials Engineering

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Bibliographic Details
Main Author: Hasan Issa, Dawood
Other Authors: Kahtan S., Mohammed, Dr.
Format: Thesis
Language:English
Published: Universiti Malaysia Perlis (UniMAP) 2015
Subjects:
Friction stir welding
Aluminum
Copper alloys
Alloys
Online Access:http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77200
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spelling my.unimap-772002022-11-25T01:15:00Z The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys Hasan Issa, Dawood Kahtan S., Mohammed, Dr. Friction stir welding Aluminum Copper alloys Alloys Doctor of Philosophy in Materials Engineering In this work, main similar (6061 aluminum alloy) and dissimilar (commercially pure aluminum and copper) materials were butt joined via friction-stir welding (FSW). The influence of FSW parameters, namely, small pin geometry, rotational speed, welding speed, and surface roughness of material, on the macrostructure, microstructure, and mechanical properties of only similar material joint characteristics were evaluated. The effects of FSW tool rotational speeds, with and without preheating on the copper side for dissimilar material joints, were also examined. For tool pin geometry, the triangular tool pin profile produced the most feasible metallurgical and mechanical weld properties among other tool pin profiles. Furthermore, the lowest tensile strength and microhardness were obtained for the joint FSW with square tool pin profile. Smaller tool pin profiles and shoulder diameter led to narrow heat-affected zone (HAZ) and a desired softening level. The 6061 aluminum alloy workpieces stirred by friction were welded at different tool rotational speeds and treated with and without reinforcement of 10 vol. % SiC powder from the welding volume. The results indicated the presence of the optimal mechanical properties when the joint was fabricated at 1750 rpm rotational speed because of the pinning effect and enlarged nucleation sites associated with the insertion of SiC powder in the welding zone. The results also revealed that the ultimate tensile strength (UTS) was significantly enhanced by approximately 52% of the base material (6061 aluminum alloy), at 1750 rpm because of the effect of the SiC powder. All process parameters used in this research significantly affected the microstructure and mechanical properties. The results also indicated that the welding speed significantly influenced the joint microstructure and mechanical properties when reinforced with SiC powder. Results demonstrated that spherical nano-sized grains of the joints were produced when the top surface of the workpieces ground smoothly (i.e.98, 60, 51 and 37 nm). Experimental results also indicated that the tensile strength of FSW 6061 aluminum alloy was notably affected by the joining process at different selected values of workpiece surface roughness. However, Vickers microhardness was improved in the HAZ because of the effect of surface roughness, which narrowed the width of this zone. The FSW of commercial pure aluminum and copper demonstrated high bonding strength when preheated on the copper side compared with the optimal joint of the specimen conducted without preheating. Furthermore, X-Ray Diffraction (XRD) data showed that changes in metal alloy crystallite sizes, densities, and lattice parameters occurred over the test distances at different rotational speeds. The grains were fine and dynamically recrystallized near the weld interface and elongated at various distances. The fracture surfaces showed varied results when different parameters were used. These surfaces presented either ductile or brittle fracture. 2015 2022-11-25T01:13:15Z 2022-11-25T01:13:15Z Thesis http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77200 en Universiti Malaysia Perlis (UniMAP) Universiti Malaysia Perlis (UniMAP) School of Materials Engineering
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Friction stir welding
Aluminum
Copper alloys
Alloys
spellingShingle Friction stir welding
Aluminum
Copper alloys
Alloys
Hasan Issa, Dawood
The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
description Doctor of Philosophy in Materials Engineering
author2 Kahtan S., Mohammed, Dr.
author_facet Kahtan S., Mohammed, Dr.
Hasan Issa, Dawood
format Thesis
author Hasan Issa, Dawood
author_sort Hasan Issa, Dawood
title The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
title_short The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
title_full The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
title_fullStr The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
title_full_unstemmed The evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and Cu alloys
title_sort evolution of microstructures and properties due to materials tool interaction during friction stir welding of similar and dissimilar al and cu alloys
publisher Universiti Malaysia Perlis (UniMAP)
publishDate 2015
url http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77200
_version_ 1753972993923481600
score 13.214268

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