Effect of precipitation hardening heat treatment on mechanical and microstructure features of dissimilar friction stir welded AA2024-T6 and AA6061-T6 alloys

Grain growth inhibition at the heat-affected zone, improved weld strength and superior tribological properties of welds are desirable attributes of modern manufacturing. With the focused on these attributes, tungsten carbide (WC) nanoparticles were employed as reinforcements for the friction stir welding of 5-mm-thick AA5182 aluminum alloy by varying tool traverse speeds. The microstructure, microhardness, ultimate tensile strength, fracture and wear behavior of the resultant WC-reinforced welds were investigated, while unreinforced AA5182 welds were employed as controls for the study. The result shows that the addition of WC nanoparticles causes substantial grain refinement within the weld nugget. A decrease in traverse speed caused additional particle fragmentation, improved hardness value and enhanced weld strength in the reinforced welds. Improved wear rate and friction coefficient of welds were attained at a reduced traverse speed of 100 mm/min in the WC-reinforced welds. This improvement is attributed to the effects of reduced grain size/grain fragmentation and homogeneous dispersion of WC nanoparticles within the WC-reinforced weld nugget.

Mechanical Properties and Wear Behavior of AA5182/WC Nanocomposite Fabricated by Friction Stir Welding at Different Tool Traverse Speeds

This paper investigates the effect of different tool pin morphologies on the inter-mixing capability, microstructure, mechanical properties, corrosion, fracture, and wear behaviors of the dissimila...

Role of Mg2Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg2Si composite:

Large and irregular particle sizes of B4C in the Mg matrix are performance-impeding challenges of the as-cast Mg-B4C composites. In an attempt to overcome this, the secondary solid-state friction stir processing of the as-cast Mg-10%B4C composite with a flow-enhancing double-pin tool was carried out and the ensuing result was compared with that of a single-pin tool. The microstructure, hardness, tensile strength, wear, and the fractured surface of the processed composites were investigated and compared. The extra pin-shearing effect and the complex pin-induced interactive material flow of the double-pin tool induce better refinement of the B4C particles in the Mg-10%B4C composite. The use of a double-pin tool increases the stirred and recrystallized vortex/swirl width, kernel average misorientation (KAM) fraction, dislocation density, hardness value at the stirred center (117 HV), and tensile strength (194 MPa) of the Mg-10%B4C composite as compared to the single-pin tool. The double-pin tool changes the fracture path of the composite away from the stirred center owing to the improved material flow and properties of the stirred center. The tribological properties (weight loss, wear rate, and coefficient of friction) of the processed composites are equally improved by the double-pin tool. A double-pin tool is thus recommended for the improvement of material flow, particle-disintegration, mechanical and tribological properties of Mg-based metal matrix composite.

Improvement of mechanical and wear behavior by the development of a new tool for the friction stir processing of Mg/B4C composite

Nanomaterial reinforced friction stir welding (FSW) is an emerging domain, as it delivers a promising method for enhancing joint properties by making composite joints. Composite joints can enhance surface properties like hardness, strength, corrosion resistance, wear resistance, fatigue life, electrical conductance. Over few years many publications have been reported on the application of nanoparticles reinforcement in FSW joints. The present review critically analyses the current status of nanoparticle reinforcement FSW process. Firstly need, type, behaviour, intrinsic properties of nanoparticles used in FSW are discussed. Then, the microstructural examinations of reinforced joints are analysed. Followed by, various properties associated with reinforced joints are presented with the mechanism of the relationship between microstructure and properties. Finally, various methods of deposition of nanoparticle in FSW is discussed. At last prospects of reinforced FSW are explored followed by concluding remarks.

A review on nanomaterials reinforcement in friction stir welding

In this study, the Friction stir spot welding (FSSW) of 2024-T3 aluminum alloy with 1.6 mm thickness was investigated. The effects of the silicon carbide (SiC) nanoparticles on the metallurgical and mechanical properties were discussed. The effects of particles on tensionshear and wear tests were also investigated. The process was conducted at a constant rotational speed of 1000 rpm. Results showed that adding SiC nanoparticles to the weld during FSSW had a major effect on the mechanical properties. In fact, the addition of nanoparticles as barriers prevented grain growth in the Stir zone (SZ). The data obtained in the tensile-shear and wear tests showed that tensile-shear load and wear resistance increased with the addition of SiC nanoparticles, which was attributed to the fine grain size produced in the SZ.

Mahsa Laali Sarab

Papers

Friction stir spot welding of 2024-T3 aluminum alloy with SiC nanoparticles