In this study, a hybrid surface composite of AA5083/SiC-Gr was produced by Friction Stir Processing (FSP). Reinforcement material each in 50:50 proportion was filled in the base matrix using holes method. Three different hybrid reinforcement volumes of 301.6 mm ³, 452.4 mm ³, and 603.2 mm ³ were prepared for surface composite. Optical and Scanning Electron Microscopy was used to check the quality of the prepared surface composite and homogeneous distribution of reinforcement was observed in the images. It was observed that due to better uniform distribution of reinforcement particles during 3 pass FSP, specimens with 301.6 mm ^3/ reinforcement volume showed enhanced microhardness and wear properties in comparison with the other specimens. Keywords: Surface Composites; Multi-pass; Friction Stir Processing; Reinforcement; Hybrid Composite

The main aim of this work was to obtain a copper matrix surface composite using friction stir processing (FSP). The reinforced phase was SiC particles with an average size of 5 mm. The effect of the reinforcement on the microstructure, hardness and wear behaviour were analysed. The friction treatment was carried out using a truncated cone-shaped tool with a threaded side surface. Multi-chamber technology was used to produce the composite microstructure in the copper surface layer. Changes in the material microstructure were assessed by light microscopy and scanning electron microscopy. Comparative measurement of the hardness of the initial and treated material as well as wear resistance tests were also carried out. A favourable effect of the surface treatment on the microstructure and properties of the copper was found. As a result of the friction treatment there was strong grain refinement in the copper surface layer. The average grain size in the stirring zone was about 3 mm and was over 21 times smaller than the average grain size in the initial material. Intensive dispersion of the SiC particles in the modified layer was also found, leading to the formation of a copper matrix composite. The effect of microstructural changes in the surface layer of the material and formation of the surface composite was an over two-fold increase in the hardness of the material and an increase in wear resistance.

Nowadays, Aluminium (Al) based hybrid surface composites are amongst the fastest developing advanced materials used for structural applications. Friction Stir Processing (FSP) has emerged as a clean and flexible solid-state surface composites fabrication technique. Intensive research in this field resulted in numerous research output; which hinders in finding relevant meta-data for further research with objectivity. In order to facilitate this research need, present article summarizes current state of the art and advances in aluminium based hybrid surface composites fabrication by FSP with in-situ and ex-situ approach. Reported literature were read and systematically categorized to show impacts of different types of reinforcements, deposition techniques, hybrid reinforcement ratio and FSP machine parameters on microstructures, mechanical and tribological characteristics of different Al alloys. Challenges and opportunities in this field have been summarized at the end, which will be beneficial to researchers working on solid state FSP technique.

In the current study, wear performance of pure magnesium (Mg) and composite fabricated with titanium carbide (TiC) reinforcement is investigated under various loading and sliding velocity conditions. The Mg-matrix composite is prepared by friction stir processing (FSP) carried out at optimized values of process parameters. Sliding wear tests on Mg and friction stir processed (FSPed) Mg+TiC surface composite were done on pin-on-disc configuration. The consequence of the normal load applied and sliding velocity on wear behaviour of the two materials is evaluated by performing the tests at two normal loads of 6 N and 12 N and three sliding speeds of 0.5 m/s, 1.5 m/s and 4.5 m/s. FSPed composite found to exhibit an enhanced wear resistance as compared to that of pure Mg. To get an insight into the possible types of mechanisms for wear of the composites sample under varying load and sliding speeds conditions, the worn test specimens are subjected to scanning electron microscopy (SEM). SEM/EDS analysis revealed that oxidation, ploughing, trailing edge and 3-body abrasive wear were the predominant mechanisms for the wear of samples at a different set of experimental conditions. The tensile strength of the FSPed surface composite was found to be 25% higher than pure Mg. Wear resistance was found to increase by about 33%.