Tsuyoshi Furushima

The heterogeneous deformation of polycrystalline metals inherently originates from the intergranular deformation incompatibility. This paper proposes physical parameters related to the crystal orientations, the Schmid factor of the most activated slip system, and the misorientation angle to characterize the deformation incompatibility between the adjacent grain couple. A comprehensive multiscale investigation is conducted to reveal the mechanism from intergranular deformation incompatibility to

Magnesium (Mg) alloy stents are expected to be the next generation of stents because of good biocompatibility and biodegradability. Compared with cold drawing, dieless drawing with local heating is an effective method for manufacturing the Mg alloy microtubes since a large reduction in area can be achieved in a single pass. However, the microstructure and properties of dieless drawn tubes have not been clarified, leading to the problems in practical application of dieless drawn tubes. In this st

Compared to cold drawing, dieless drawing has shown great potential for manufacturing biodegradable Mg alloy microtubes due to the large reduction in area acquired in a single pass. However, owing to the local heating and local deformation, the deformation mechanism during dieless drawing is not clear, and thus causing difficulties in controlling the microstructure of dieless drawn tubes. For the purpose of acquiring a desired microstructure, in this study the deformation mechanism of ZM21 Mg al

An uni-axial tensile test is one of the general methods to obtain plastic properties for estimating deformation behavior of materials in the simulation of practical metal forming process. Non-contact measurement is generally used because of determination of accurate plastic properties excepting for contact effects. In the conventional method, strain distribution of specimen sprayed with random pattern is measured by digital image correlation (DIC). However, sprayed treatments on the specimen sur

A Finite element (FE) model considering mesoscopic material inhomogeneity due to a different flow stress for each crystal grain to predict free surface roughening is proposed. The effect of the standard deviation of the material inhomogeneity and grain size was investigated by the 2D FE model. In addition, to verify the model considering material inhomogeneity, the free surface roughening behavior is predicted under a bi-axial tension state using the 3D FE model. Furthermore, by comparison with

Dieless drawing technique, which can achieve a large reduction in the area of metal tubes in a single pass by local heating and cooling, is a flexible metal drawing process without dies. In this study, we suggested the effective drawing path control in the early drawing stage to restrain the unstable deformation, which leads to fracture. The actual deformation limit of the material is evaluated by coupled thermo-mechanical finite element analysis and experiments of the dieless drawing. The metal

Micro metal forming with metal foils is one of the promising approaches to fabricate micro parts. In this study, a finite element (FE) model for metal foil considering material inhomogeneity due to different flow stresses for each crystal grain to predict free surface roughening and necking behavior is suggested. Material used is pure copper C1020-O, pure aluminum 1N30-O and pure titanium TR270C-O with thickness of 0.05mm. Material inhomogeniety parameter of variation in α value is determined by