The single-crystal yield surfaces of bcc crystals for slip on {123}<111> systems have been analyzed systematically and derived based on the Taylor/Bishop-Hill theory. It is found that there are 338 stress states altogether. All the stress states are classified according to the crystal symmetry. The results demonstrated that there are 14 groups of yield vertices, which activate five, six, or eight slip systems, depending on the crystallographically nonequivalent groups. In addition, the four groups of yield vertices that Chin and Wonsiewicz[15] did not consider have been obtained(there are 126 stress states). Among all these vertices, the fraction of vertices for which there is slip ambiguity (more than five active slip systems) is reduced considerably to 146/338 (≈43 pct). By means of the stress states obtained by Chin et al. and by the present authors, respectively, the plastic flow for axially symmetric deformation and three-axial deformation have been analyzed. In the case of axially symmetric deforma-tion, the results are the results are the same using the two different kinds of stress states. The obtained new stress states are necessary in order to analyze the three-axial deformation.

A new approach to manufacture metal/polymer macro-composite components is presented, in which the injected polymer melt from the injection machine forces the sheet metal blank to deform according to the contour of the mould and the space between the formed sheet blank acts as the moulding cavity of the polymer melt. As the melt cools down, it adheres to the surface of the formed sheet blank. The mechanism of adhesion bonding between the polymer and the surface of the formed sheet blank is discussed briefly. The deformation characteristics and evolution of plastic strains of the sheet blank during the manufacturing process, the distribution of plastic strains and thickness of the formed sheet blank, and the effects of drawing-in of the flange on these have been analysed by the finite element method and experiment. According to deformation characteristics, the formed sheet blank can be divided into five regions. It is shown that deep drawing is the dominating process when the pressure increases from 0 to about 30 MPa; after this stage, stretch forming of the sheet blank that has already been in the mould cavity is the dominating process and two highly strained zones with severe thickness reduction are developed.

The microstructures of the adiabatic shear hand (ASB) on the pure titanium side in the titanium/mild steel explosive cladding interface were investigated by means of OM, SEM and TEM. Very small equiaxed grains (<0.1 μm) with a low dislocation density were observed in ASB. These results were discussed in terms of dynamic recrystallization, that is enabled by the adiabatic temperature rise associated with plastic deformation. This dramatic microstructural refinement enables a thermo-mechanical response that may lead to a superplastic deformation in ASB. The reasons that ASBS occurred only on the titanium side and not on the mild steel side were discussed. And which was related to the differences in physical, mechanical, thermal properties and crystal structure between titanium and mild steel.