scholarly journals THE EFFECT OF NANOSCALE DEFECTS ON THE DYNAMIC YIELD STRESS OF ALLOYS

Author(s):  
Вадим Викторович Малашенко ◽  
Татьяна Ивановна Малашенко

Теоретически проанализирована высокоскоростная деформация состаренных сплавов, содержащих зоны Гинье-Престона. Получено аналитическое выражение вклада зон Гинье-Престона в величину динамического предела текучести. Показано, что динамическое торможение дислокаций наноразмерными дефектами существенно отличается от торможения точечными дефектами. The high strain rate deformation of aged alloys containing Guinier-Preston zones is theoretically analyzed. The analytical expression for the contribution of the Guinier-Preston zones to the value of the dynamic yield stress has been obtained. It is shown that the dynamic drag of dislocations by nanoscale defects differs significantly from the drag by point defects.

2021 ◽  
Vol 63 (12) ◽  
pp. 2070
Author(s):  
В.В. Малашенко

The high-strain rate deformation of crystals with giant magnetostriction is theoretically analyzed. It is shown that giant magnetostriction has a significant effect on the dynamic yield stress of crystals.


Author(s):  
Вадим Викторович Малашенко ◽  
Татьяна Ивановна Малашенко

Теоретически проанализирована высокоскоростная деформация сплавов, содержащих зоны Гинье-Престона, в условиях высокоэнергетических внешних воздействий. Анализ выполнен в рамках теории динамического взаимодействия структурных дефектов. Исследуемый механизм диссипации заключается в необратимом переходе энергии внешних воздействий в энергию дислокационных колебаний. Получено аналитическое выражение динамического предела текучести с учетом всех структурных дефектов, содержащихся в сплаве. Показано, что в условиях высокоэнергетических внешних воздействий наноразмерные дефекты влияют на характер зависимости механических свойств от концентрации атомов второго компонента. Зависимость динамического предела текучести от концентрации атомов второго компонента становится немонотонной и имеет минимум. Выполнены численные оценки концентрации, при которой предел текучести становится минимальным. При таком значении концентрации происходит переход от доминирования торможения дислокации зонами Гинье-Престона к доминированию торможения атомами второго компонента. The high strain rate deformation of alloys containing Guinier-Preston zones under high-energy external influences has been theoretically analyzed. The analysis was carried out within the framework of the theory of dynamic interaction of structural defects. The investigated dissipation mechanism consists in the irreversible transfer of energy of an external impact into the energy of dislocation vibrations. An analytical expression for the dynamic yield stress taking into account all structural defects of the alloy has been obtained. It is shown that, under high-energy external influences, nanoscale defects affect the nature of the dependence of mechanical properties on the concentration of atoms of the second component. The dependence of the dynamic yield stress on the atomic concentration of the second component becomes nonmonotonic and has a minimum. Numerical estimates of the concentration corresponding to the minimum yield stress has been made. At this concentration value, a transition occurs from the dominance of the dislocation drag by the Guinier-Preston zones to the dominance of the drag by the atoms of the second component.


1998 ◽  
Vol 83 (9) ◽  
pp. 4660-4671 ◽  
Author(s):  
C. J. Shih ◽  
V. F. Nesterenko ◽  
M. A. Meyers

2011 ◽  
Vol 88-89 ◽  
pp. 674-678
Author(s):  
Shuang Zan Zhao ◽  
Xing Wang Cheng ◽  
Fu Chi Wang

Some results of an experimental study on high strain rate deformation of TC21 alloy are discussed in this paper. Cylindrical specimens of the TC21 alloys both in binary morphology and solution and aging morphology were subjected to high strain rate deformation by direct impact using a Split Hopkinson Pressure Bar. The deformation process is dominated by both thermal softening effect and strain hardening effect under high strain rate loading. Thus the flow stress doesn’t increase with strain rate at the strain hardening stage, while the increase is obvious under qusi-static compression. Under high strain rate, the dynamic flow stress is higher than that under quasi-static and dynamic flow stress increase with the increase of the strain rate, which indicates the strain rate hardening effect is great in TC21 alloy. The microstructure affects the dynamic mechanical properties of TC21 titanium alloy obviously. Under high strain rate, the solution and aging morphology has higher dynamic flow stress while the binary morphology has better plasticity and less prone to be instability under high strain rate condition. Shear bands were found both in the solution and aging morphology and the binary morphology.


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