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In the present study, a new methodology of using free–free beam method coupled with circle-fit approach is used to determine damping of ceramic reinforced magnesium composites. This technique is based on classical vibration theory, by which the geometry and material properties of the metal matrix composites are related to resonant frequency and structural damping of the test specimen. Using the fact that the ratio of the vibration response to the applied force fits to a circle in the Argand plane for each resonant frequency of the test specimen, the damping factor and natural frequency is predicted accurately for the test specimen. An attempt is made to rationalize the increase in damping capability of the MMC when compared against the monolithic specimen in terms of increase in dislocation density and presence of plastic zone at the matrix–particulate interface.

a b s t r a c tIn this study, T-Shape friction test was redesigned to make it more suitable for application to microforming processes. Workpiece with aspect ratio (length/diameter) of 5 was proposed in order to ease workpiece handling. The die geometry was also modified from the original test to improve friction sensitivity especially within the range of friction factors commonly observed in metal forming. Geometric deviation of the die was simulated using Deform-2D to establish the acceptable tolerance for the fabrication. The effect of variation in workpiece mechanical properties on the test behavior was also investigated through Deform-2D simulation. Based on simulations on a 1 mm diameter copper workpiece, a tolerance of 0.01 mm (1% of workpiece diameter) was found to be the most suitable for the die fabrication. In addition, it was shown that variations in workpiece mechanical properties of up to 10% do not significantly influence the friction test results. Ultimately, T-Shape test experiment was conducted using copper workpieces to examine how the test complied with the friction behavior observed in the experiment.