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The formation behavior of Secondary Reaction Zone (SRZ) for a 4 th generation nickel-base single crystal (SC) superalloy with aluminide coating was investigated. The growth of SRZ is supposed to be dominantly controlled by the inward diffusion of aluminum from the coating layer to the substrate. The outward diffusion of Ru from the substrate to the coating layer may also contribute to SRZ formation. A remarkable reduction of SRZ was accomplished by depositing thin films composed of Co and/or Ru on the alloy surface prior to aluminide coating, that is expected to restrict the diffusion of Al and Ru between the coating layer and the substrate.

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Post irradiation annealing (PIA) clarified the induced versus enhanced controversy regarding nanoscale Mn-Ni-Si precipitate (MNSP) formation in pressure vessel steels. Radiation induced MNSPs would dissolve under high temperature PIA, while radiation enhanced precipitates would be stable above a critical radius (rc). A Cu-free, high Ni steel was irradiated with 2.8MeV Fe 2+ ions at two temperatures to generate MNSPs with average radii (̅) above and below an estimated rc for PIA at 425°C up to 52 weeks. Atom probe tomography and energy dispersive x-ray spectroscopy showed MNSPs with r< rc dissolved, while those with r>rc slightly coarsened, consistent with thermodynamic predictions.

Based on the idea of synergy to explore the building blocks of movements, this study focused on the muscle space for reaching movements by human upper limbs on a horizontal plane to estimate the relationship among muscle synergies, equilibrium-point (EP) trajectories, and endpoint stiffness in two ways: (1) a novel estimation method that analyzes electromyographic signals under the concept of agonistantagonist (A-A) muscle pairs and (2) a conventional estimation method that uses mechanical perturbations. The experimental results suggest that (1) muscle activities of reaching movements by human upper limbs are represented by only three functional muscle synergies; (2) each muscle synergy balances the coactivations of A-A muscle pairs; (3) two of the muscle synergies are invariant bases that form an EP trajectory described in polar coordinates centered on a shoulder joint, where one is a composite unit for radial movement and the other is for angular movement; and (4) the third muscle synergy is the invariant basis for additional adjustment of the endpoint stiffness and has some influence on the direction and size of the endpoint stiffness ellipse.

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