Метод расчета напряженного состояния, обусловленного динамическим микродвойником

Abstract

На основании методов модели нетонкого некогерентного микродвойника с непрерывным распределением двойникующих дислокаций на двойниковых границах разработан способ расчета напряженного состояния у динамического двойника в случае отсутствия дополнительной генерации источником двойникующих дислокаций. В модели учтено, что в этом случае двойник имеет как когерентные, так и некогерентные участки границ. Разработанная модель в расчетах напряженно-деформированного состояния у динамического двойника позволила учесть форму некогерентных участков двойниковых границ. Установлено, что локализованные напряжения мигрируют вместе с некогерентными участками двойника.

Method for calculation of the stressed state in a dynamic twin has been developed on the basis of a non-thin non-coherent micro-twin model with continuous distribution of twinning dislocations at twin boundaries. In this case there is no additional generation with the help of twinning dislocation source. 'Hie model takes into account that the twin has coherent and non­ coherent boundary sections. The developed model has made it possible to take into consideration a form of non-coherent sec­ tions of twinning boundaries in calculations of stressed and deformed state at dynamic twins. It has been established that lo­ calized stresses arc migrating together with non-coherent sections of the twin Normal stresses cr^. change their sign in relation to direction of the twin development. Shear stresses <% are alternating in signs in relation to an axis which is perpendicular to the direction of the twin development and which is passing through a mid-point of non-coherent twin sectioa Distribution of stresses o\y и ап has similar configuration. Stresses aa in the second and fourth quarters of XOY plane are negative and the stresses in the first and third quarters are positive. Distribution of stresses o„ practically does not differ from distribution of stresses Cyy according to configuration but numerical values of stress tensor component data arc different. The results have been obtained without thin twin model that permits to consider only elastic stage of the twinning process. The executed stress calculations at dynamic twin are important for forecasting at the accumulation stage of damage origina­ tion which is caused by twinning destruction and permit to improve forecasting accuracy of technical system resources on the basis of twinning materials such as alloys based on iron, copper, zinc, aluminium, titanium.