A novel approach to enhance thermal transport in Al based hybrid composites with functionally graded layers through PM route
A novel approach to enhance thermal transport in Al based hybrid composites with functionally graded layers through PM route
Monday, October 20, 2025: 3:40 PM
In this study, we employed powder metallurgy techniques to fabricate a light-weight, high-strength hybrid reinforced aluminum metal matrix functionally graded composites (FGCs). The investigation focused on the influence of carbon nanotubes (CNT), yttrium oxide (Y2O3), and silicon carbide (SiC) reinforcements on various aspects including structure, morphology, phase composition, thermal stability, and mechanical properties of the FGCs.
Continuous variation of CNT and Y2O3 (0-2.5 wt.%) were done simultaneously to prepare a graded structure upon consolidation. Mechanical and micro structural characterizations were carried out with the aid of SEM-EDS, instrumented indentations to establish structure property co-relation. A Further characterization of the composite materials was conducted using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), indentation techniques and dynamic mechanical analyser (DMA). We found that milling the materials for more than 20 hours resulted in the uniform distribution of CNT, SiC, and Y2O3 within the aluminum matrix. Subsequent cryomilling (CM) with a ball-to- powder ratio of 100:1 further reduced agglomeration and effectively cleaved the nanotubes, thereby minimizing entanglements. XRD analysis revealed the formation of feasible reaction products during the processing steps. Thermal properties characterized through dynamic mechanical analyser (DMA) setup shows approx 50% reduced coefficient of thermal expansion values for the bulk FG composites and indicates promising stability at higher temperatures and solving the barrier issues for advance applications. Attempt were made to establish the thermal expansion pattern and its mechanism with focused studies on interfacial transitions.
Continuous variation of CNT and Y2O3 (0-2.5 wt.%) were done simultaneously to prepare a graded structure upon consolidation. Mechanical and micro structural characterizations were carried out with the aid of SEM-EDS, instrumented indentations to establish structure property co-relation. A Further characterization of the composite materials was conducted using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), indentation techniques and dynamic mechanical analyser (DMA). We found that milling the materials for more than 20 hours resulted in the uniform distribution of CNT, SiC, and Y2O3 within the aluminum matrix. Subsequent cryomilling (CM) with a ball-to- powder ratio of 100:1 further reduced agglomeration and effectively cleaved the nanotubes, thereby minimizing entanglements. XRD analysis revealed the formation of feasible reaction products during the processing steps. Thermal properties characterized through dynamic mechanical analyser (DMA) setup shows approx 50% reduced coefficient of thermal expansion values for the bulk FG composites and indicates promising stability at higher temperatures and solving the barrier issues for advance applications. Attempt were made to establish the thermal expansion pattern and its mechanism with focused studies on interfacial transitions.
Keywords: Mechanical Milling, Spark Plasma Sintering, Mechano-thermal processing, Powder Metallurgy, Nano Composites, Carbon Nanutubes, Cryomilling,
Functionally graded Materials
See more of: Processing and Characterization of Materials II
See more of: Materials Behavior & Characterization
See more of: Materials Behavior & Characterization