The growth or the attenuation of the external load

The growth or the attenuation of the external load increases the augend in Eq. (1) and transmits the ordered motion to twinning dislocations in the twinning plane and in the twinning direction. The interaction of a twin with stoppers in metals slows down its growth and contributes a component influencing the dislocation assembly to the inelastic forces. The defects of various nature and power which disturb the crystal structure generate local fields of elastic stress in a crystal with their sign and intensity being impossible to take into consideration in the process of deformation development. When summarized, the mechanic stress caused by the pyramid, twins and structure defects produce a complex field of mechanic stress. Local noncompensated fields of elastic stress appear in the deformation zone with the stress rate and the sign at any point around the imprint being impossible to identify definitely. The balance of the wedge-shaped twinned interlayer under load can be described by the following equation: where the third component characterizes the forces acting on the twinning dislocation assembly from a summary field of the elastic stresses. Probably, it is the rate and the sign of the forces responsible for a nonsynchronous, ambiguous dimensional change of wedged twins under load. If this calpain inhibitor 1 manufacturer is correct, the reversibility phenomenon is mostly expressed in the twins situating in the places of the biggest distortion of the crystal structure with the most complex pattern of local overstress, that is, near the imprint boundaries, in the twins with branchy structure and near large twin interlayers. This is convincingly proved experimentally. It was noted that interlayers of two types disappear most often: small twins near the contour of the imprint and the twin arms originating at the curved boundary of a wedge-shaped twin (Fig. 2). The appearance of a new larger twin near the existing twins is always accompanied by a partial detwinning of the nearest interlayer (Fig. 3). It is apparent from Fig. 4 that twinned wedge 3 with incoherent boundaries does not only block the development of a smaller neighboring interlayer 2 by its elastic stress field but also leads to its degradation. The appearance of new twins and the development of twins in groups unpredictably change the pattern of the heterogeneous spatial field of elastic stress near the imprint. The character of change in the twin dimensions can alter in the process of a stepwise load increase (Fig. 5). The twin embryo between interlayers 1 and 2 (Fig. 5a) grows with load increment in a way that leads to a partial detwinning of both neighboring interlayers (Fig 5b). It is noteworthy that in accordance with the considerations given above, all reversible repeated plastic shears at the boundaries take place near the boundary of the imprint and do not at the top of a twin. With further growth of the external force, twin 1 which had preferential development produces a powerful field of elastic stress with a reversed sign that leads not only to a size decrease of the neighboring twin 3 but also to the complete disappearance of a considerably long section of a more distant twinned interlayer 2. It is easier to simulate the disappearance of a wedge-shaped twin as externally, this phenomenon is absolutely similar to elastic detwinning. It is realized by the process of reversion movement of twinning dislocations from the top of the wedge to the basis and their exit out of the crystal. It is interesting that the fraction of the disappearing twins does not virtually depend on the value of the acting load (Fig. 6a). The probability of detwinning for a certain twin increases with a decrease in the parameter h/L but its value is not defined uniquely. It is evident that the main stimulus of the inverse lattice restructuring is the energy gain due to a decrease of the internal division surfaces. Local fields of elastic stress with the opposite sign created by accumulation of dislocations in the neighborhood of the pyramid imprint such as perfect dislocation forming slip lines and partial dislocations at the boundaries of wedge-shaped twins play a key role in the reversible twinning boundary displacement (Fig. 6b).