Papers by Author: Kimihiro Ozaki

Abstract: An attempt to prepare Fe2VAl deposited film and the thermoelectric module using RF sputtering has been made. Sputtering target has been prepared using mechanical alloying of metallic powders and the subsequent pulse current sintering process. The obtained deposited film has had a lack of aluminum content compared to the composition of the starting material. Controlling of aluminum content for the preparation of Fe2VAl sputtering target has made it possible to obtain the desired material composition. The film has had the experimental thermoelectric force being similar to the one estimated from the measured thermoelectric data of the materials. Fe2VAl thermoelectric module of eight pairs with a film thickness of 4 μm has had an electric force of 31mV and 5.6μW.

Abstract: In this paper, the strength of the singular stress field near the ends of the CNTs in composites was analyzed to clarify the effects of the CNT length on stress filed in the CNT reinforced composites when studying the fracture toughness. The singular stress field was separated into two types of singularities, symmetric and skew-symmetric, near the ends of CNTs according to the deformation and loading types. The stress intensity factors of the singular stress field were calculated for these two types of singularities. The effects of the CNT length in CNT reinforced composites on these stress intensity factors were investigated.

Abstract: In this work, we investigated the influences of residual stress on the load shifts, irreversible work from load vs. depth curves. It is found that there are linear relationships between the level of surface residual stress, the load shifts, and the variation of irreversible work for Ni, Ti, TiFe and A316L studied in this work. From these effects of residual stresses on load versus depth curves, depth-sensing indentation can be expected as a non-destructive method for measuring the residual stresses. Using the simulation results, the stresses estimated from the relationship of the level of surface residual stress and the load shifts, agree well with the applied stresses during simulations.