The surface composites of aluminum alloys have a higher scope of applications encountering surface interactions in the aerospace, automobile, and other industries compared to the base aluminum alloys. The friction stir process (FSP) is recently the preferred method to prepare aluminum-based surface composites due to its capability to produce improved physical properties and refined microstructure at the surface. The study examines the Al6061 alloy-based surface composite fabricated by FSP for their wear behavior and microstructure. In this study, the Al6061 alloy-based hybrid surface composites are prepared with varying weight% of copper and graphite microparticles mixture as reinforcement by FSP with two tools having unique pin profiles, i.e., threaded cylindrical and plain cylindrical. These prepared composites are investigated for the dry sliding wear test on a pin-on-disc test set-up. The experiments are designed using the L9 orthogonal array and analyzed by the Taguchi approach to obtain the influence of disc speed, load, and reinforcement weight% on wear rate. The significant parameters influencing the wear rate of the samples tested are obtained using ANOVA. Later the effects of the friction stir process and the wear tests on the microstructure of the workpieces are investigated using FE-SEM/EDS tests. It is concluded that the decrease in wear rate with the rise in reinforcement weight% (Cu + graphite) from 2% to 6%. The load has the maximum effect on the wear rate for the samples prepared by threaded cylindrical FSP tool pin profile, while reinforcement weight% affects significantly the wear rate of the samples prepared by FSP with plain cylindrical pin profile tool.

The friction stir process (FSP) is becoming a highly utilized method to manufacture composites since it refines the microstructure and improves the physical characteristics like hardness, strength, and wear resistance of their surfaces. In this study, the hardness and wear behaviours of Al6061-based surface composites prepared by the FSP were investigated and compared for the influences of various parameters—FSP tool geometry, reinforcement composition, number of FSP passes, pin load, etc. The Taguchi design with an L27 orthogonal array was developed to analyze the influence of five input parameters on the output parameter, i.e., wear rate during wear tests. The hardness of the composite samples for different reinforcement compositions was investigated, and the results were statistically compared with the obtained wear rates. It was concluded from the results that various parameters influenced the surface wear and hardness of the composites. Tool geometries cylindrical pin and square pin had the maximum and minimum wear rates, respectively. Additionally, the optimal composition of the reinforcements copper and graphene as 1:3 possessed the maximum wear rate and minimum hardness. However, the reinforcement composition 3:3 (Cu:Gr) by weight had the minimum wear rate and maximum hardness. The higher the FSP pass numbers, the lesser the wear rate and the higher the hardness, and vice-versa. This work helps identify the influence of numerous factors on the wear and hardness aspects of surface composites prepared by the FSP. In the future, this study can be modified by combining it with thermal analysis, sensor data analysis of the composites, and optimization of the parameters for desirable microstructure and physical properties.

Aluminium alloys, having high strength, ductility, and toughness, are useful structural materials. Composites of these with ceramic reinforcements improve the hardness and wear resistance, making them suitable for use in the aerospace and automobile industries. Since surface properties play a crucial role for most applications, the manufacturing of surface composites of aluminium alloys is recommended. For this purpose, Friction stir processing
(FSP) is being utilized nowadays. It refines the microstructure with a homogeneous dispersion of reinforcements into the matrix and improves physical properties like surface hardness, wear resistance, strength, etc., while retaining the properties of remaining volume.
The study aims to investigate and compare the temperature and vibration sensor data while manufacturing Al6061 alloy-based surface hybrid composites by using two different FSP tools. The FSP method is used for the fabrication of Al6061 alloy based composites with the copper and graphite powders mixture (1:1), reinforced into the matrix surface by using two
H13 tools with two different pin profiles - threaded cylindrical and plain cylindrical. Holes of different diameters and depths are drilled on the Al6061 matrix for reinforcement addition.
This FSP process is investigated using a thermal gun and a Cross-Domain Development kit for temperature and vibration measurement. It is verified that both the temperature and vibration values are lower in the composites fabricated by FSP tool with threaded pin profile than that by FSP tool with plain pin profile. The processed samples are later investigated for the microstructure by Field Emission Scanning Electron Microscope and Energy-Dispersive
X-Ray Spectroscopy tests. The reinforcements are dispersed more uniformly by the FSP tool with threaded cylindrical profile. This research can be used to further monitor and control properties like temperature, vibration, force, current, etc., to obtain a uniform reinforcement dispersion with improved mechanical properties during the surface composite preparation by FSP.

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