Tensile properties and microstructural features of friction stir welded Al 6061 joints fabricated by various dual-pin tool shapes

The present study investigates the influence of tool pin profiles on microstructure and mechanical properties of friction stir welded AA 6061-T6 Alloy was studied. An attempt is made here to review the fundamental principle of this process its tensile strength and examination of its metallurgical consequences. An improved milling machine is fabricated for performing friction stir welding and its effectiveness in joining Al 6061-T6 Alloy plates is demonstrated in the current work. The FSW Process has proved to be very efficient and has immense potential for future application. Present investigation is to find out the optimum mechanical properties of friction stir welding of Al 6061-T6 alloy &Mg AZ31B alloy. In this present study an attempt has been made to study the effect of tool rotational speed, traversing speed and tool pin profiles (Taper Thread profile) on FSW zone transformation in Al and Mg alloys. For three different tools, rotational speeds, three different traversing speeds, and three different tool D/d ratios, one tool pin profile have been used to fabricate the joints. The formation of FSW of Al 6061 of fusion zone has been evaluated and correlated with base metal. Tensile properties, toughness and microstructure of the joint were evaluated and correlated as received Al 6061-T6 & Mg AZ31B alloys. The joints fabricated using rotational speed of 1120rpm, a welding speed of 40 mm/min, taper thread pin profile, tool shoulder diameter of 18 mm, (D/d)=3.0 showed higher tensile properties compared to other joints.

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An appraisal of characteristic mechanical properties and microstructure of friction stir welding for Aluminium 6061 alloy – Silicon Carbide (SiCp) metal matrix composite

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.13.4.2019.07.0463 ◽

2019 ◽

Vol 13 (4) ◽

pp. 5804-5817

Author(s):

Ibrahim Sabry

Keyword(s):

Tensile Strength ◽

Ultimate Tensile Strength ◽

Metal Matrix Composite ◽

Matrix Composite ◽

Metal Matrix ◽

Welded Joint ◽

Rotation Speed ◽

Fusion Welding ◽

Friction Stir ◽

Al 6061

It is expected that the demand for Metal Matrix Composite (MMCs) will increase in these applications in the aerospace and automotive industries sectors, strengthened AMC has different advantages over monolithic aluminium alloy as it has characteristics between matrix metal and reinforcement particles. However, adequate joining technique, which is important for structural materials, has not been established for (MMCs) yet. Conventional fusion welding is difficult because of the irregular redistribution or reinforcement particles. Also, the reaction between reinforcement particles and aluminium matrix as weld defects such as porosity in the fusion zone make fusion welding more difficult. The aim of this work was to show friction stir welding (FSW) feasibility for entering Al 6061/5 to Al 6061/18 wt. % SiCp composites has been produced by using stir casting technique. SiCp is added as reinforcement in to Aluminium alloy (Al 6061) for preparing metal matrix composite. This method is less expensive and very effective. Different rotational speeds,1000 and 1800 rpm and traverse speed 10 mm \ min was examined. Specimen composite plates having thick 10 mm were FS welded successfully. A high-speed steel (HSS) cylindrical instrument with conical pin form was used for FSW. The outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt. %) was 195 MPa at rotation speed 1800 rpm, the outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt.%) was 165 MPa at rotation speed 1000 rpm, that was very near to the composite matrix as-cast strength. The research of microstructure showed the reason for increased joint strength and microhardness. The microstructural study showed the reason (4 %) for higher joint strength and microhardness. due to Significant of SiCp close to the boundary of the dynamically recrystallized and thermo mechanically affected zone (TMAZ) was observed through rotation speed 1800 rpm. The friction stir welded ultimate tensile strength Decreases as the volume fraction increases of SiCp (18 wt.%).

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