Abstract
The deformation mechanism of slips and twins has a considerable influence on the plasticity of magne-sium alloys.However,the roles of slips and twins in the room-temperature deformation of Mg-rare earth(Mg-RE) alloys with high contents of rare earth elements is rarely investigated.Here,the microstruc-tural evolution and deformation mechanism of an aged Mg-SY-2Nd-3Sm-0.SZr alloy during uniaxial compression at room temperature were systematically investigated using in-situ electron-backscattered diffraction and transmission electron microscopy.The results indicated that in the early stage of defor-mation,the Mg-RE alloy was mainly controlled by the slip of <a> dislocations in the basal plane and the coordinated c-axis strain of the {10-12} twin.With an increase in the strain,the grain orientation became more suitable for the initiation of pyramidal Ⅱ <c + a> dislocations in the later stage of deforma-tion;these dominated the deformation mechanism.In the twin evolution of the Mg-RE alloy,there were three types of twin-twin interaction behaviors:(i) single twin variant 'parallel'structure,(ii) single twin variant 'cross' structure,and (iii) multi twin variant 'cross' structure.In addition,three types of twin-grain boundary interaction behaviors were summarized:(i) twin 'refracting through'grain boundary,(ii) twin'parallel through'grain boundary,and (iii) twin 'fusing through'grain boundary,which are expected to act as new means and solutions for the twin strengthening of magnesium alloys.
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NSTL
维普
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