COLD ROLLING AND RECRYSTALLIZATION TEXTURE OF CROSS SHEAR ROLLED COMMERCIAL COPPER

The texture change along the normal direction to rolling plane of cross shear rolled commer- cial copper has been studied by means of two step method for ODF caleulation and computer simulation.The texture of cross shear rolling of copper is similar in primary components to that of conventional cold rolling,but the scattering degree and direction of the texture are dif- ferent,due to the residual shear strain change in different position along the normal to rolling plane.It seems that no more effect of the shear strain upon the recrystallization texture.

On the Taylor principles for plastic deformation of polycrystalline metals

Grain orientation evolutions and texture formation based on the Taylor principles offer important references to reveal crystallographic mechanisms of deforma- tion behaviors. Strain equilibrium between grains is achieved in Taylor theory, however, stress equilibrium has not yet been reached perfectly even in many modifications of the theory though the textures predicted become very close to those of experimental observations. A reaction stress model is proposed, in which mechanical interactions between grains are considered in details and grain deformation is conducted by penetrating and non-penetrating slips. The new model offers both of the stress and strain equilibria and predicts the same textures indicated by Taylor theory. The rolling texture simulated comes very close to the experimental observations if the relaxation effect of the non-penetrating slips on the up-limits of reaction stresses is included. The reaction stress principles open theoretically a new field of vision to consider deformation behaviors of poiycrystaliine materials, whereas the Taylor principles become unnecessary both theoretically and practically. Detailed engineering conditions have to be included in simulations if the deformation textures of industrial products should be predicted.

On intergranular mechanical interactions and the theory of deformation crystallography of metals

The equilibrium of intergranular stress and strain can be realized simultaneously,whereas five independent slip systems of the Taylor principle and the criterion of minimal internal work are unnecessary.In fact,the Taylor principle applied in current theories is incorrect both in practice and theory,in which the activation mechanism of plastic deformation systems must violate the Schmid’s law and deviate from the elastic-plastic characteristics of deformed matrix.The intergranular reaction stress(RS)during deformation can be calculated according to Hooke’s law and elastic limit without additional subjective presupposition,therefore the RS theory is established intuitively.Under the combination of the RS(the intergranular elastic effect)and the external loading the slips penetrating grains are activated and produce deformation texture,but certain non-penetrating slips near grain boundaries will become active(the intergranular plastic effect)and produce some random texture when a RS reaches the yield strength of grains.The RS theory is simple,intuitive and reasonable,based on which the texture simulation can well reproduce the texture formation of various metals under different external loadings and under different crystallographic mechanisms.