in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

The problem of determining the effective incremental response of nonlinearly elastic composite materials given some initial prestress is of interest in numerous application areas. In particular, the case when small-amplitude elastic waves pass through a prestressed inhomogeneous structure is of great importance. Of specific interest is how the initial finite deformation affects the microstructu...

We report results of uniaxial compression experiments on single-crystalline Cu nanopillars with nonzero initial dislocation densities produced without focused ion beam (FIB). Remarkably, we find the same power-law size-driven strengthening as FIB-fabricated face-centered cubic micropillars. TEM analysis reveals that initial dislocation density in our FIB-less pillars and those produced by FIB a...

The primary objective of the overall research program was to measure high-frequency broadband acoustic backscattering in highly stratified, energetic environments and to determine the contribution to scattering from temperature and salinity microstructure. Testing the validity of existing scattering models and the initial development of new, and/or extensions of existing, simple physics-based s...