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Abstract
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This study described surface reinforcing of A356 aluminum alloy with 2.5, 5, and 7.5 vol% nanolayered Ti3AlC2 MAX phase particles. The friction stir processing (FSP) was used to fabricate these surface composites. The surface composites were characterized by different routes such as optical and electron microscopy, microhardness, tensile, and wear tests. The OM and SEM micrographs showed that the application of FSP resulted in microstructural refinement and modification because of reducing porosity, diminishing coarse dendrites of primary aluminum, fragmenting of coarse silicon needle-shaped particles, uniform distributing of fine silicon particle in the substrate. This microstructural evolution led to increasing in microhardness and tensile values. The microhardness and tensile strength values of the as-received alloy and A356-7.5 vol% Ti3AlC2 surface composite were about 68 HV and 112 MPa, and 87 HV and 184 MPa, respectively. Surface nanocomposites showed significantly lower friction coefficient values and lower wear rates than the substrate. Scanning electron microscopy micrographs revealed that the abrasive wear with different extent and characteristics was the dominant wear mechanism.
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