ORALS

SESSION: MultiscaleTuePM1-R8	Horstemeyer International Symposium (7th Intl. symp. on Multiscale Material Mechanics & Sustainable Applications)
Tue. 29 Nov. 2022 / Room: Similan 1
Session Chairs: Elias Aifantis; Lev Rapoport; Session Monitor: TBA

14:50: [MultiscaleTuePM107] OS
In-situ TEM Observation and Atomistic simulation of pyramidal dislocations in c-axis compression of single crystal magnesium
Boyu Liu¹ ; Fei Liu¹ ; Bin Li² ; Jian-feng Nie³ ; Zhiwei Shan¹ ; ¹Xi'an Jiaotong University, Xi'an, China; ²UNIVERSITY OF NEVADA, RENO, RENO, United States; ³Monash University, Melbourne, Australia;
Paper Id: 79 [Abstract]

<p>Pyramidal dislocations are important dislocations that are able to accommodate the c-axis strain when a single crystal magnesium is compressed along its c-axis. Generally, pyramidal dislocations require higher stresses to activate than basal and prismatic slip systems. But the nature of these dislocations, which have very large Burgers vectors (0.612 nm), has been controversial in terms of slip plane, dislocation dissociation, and dislocation mobility. In this work, we present in-situ TEM observation of pyramidal dislocations in submicron single crystal magnesium during c-axis compression. High density pyramidal dislocations were observed, which generated a large plastic strain, in stark contrast to bulk samples. Computational tomography was conducted to analyze the slip plane of the pyramidal dislocations. The results show that both pyramidal-I and pyramidal-II dislocations were activated. Atomistic simulations were also performed and the simulation results were consistent with the in-situ TEM observations.</p>