|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Magnesium Technology 2021
||Understanding Twinning: Detwinning Behavior of Unalloyed Mg during Low-cycle Fatigue Using High Energy X-ray Diffraction
||Aeriel D. Murphy-Leonard, John Allison
|On-Site Speaker (Planned)
||Aeriel D. Murphy-Leonard
The influence of grain size and alloying on cyclic stress-strain(CSS) and low cycle fatigue (LCF) behavior in magnesium was investigated using strain-controlled, fully-reversed LCF conditions. The initial texture was so that the c-axis of most grains was normal to the loading direction to promote extension twinning during compression and the removal of those twinned regions during tension of the following cycle. In both pure Mg and Mg-4Al a tension-compression asymmetry was observed and related to twinning and detwinning. The loop shape asymmetry increased with strain amplitudes in both materials. Interactions between solutes, twins, and dislocations leads to higher hardening rate in the Mg-4Al when compared to the unalloyed condition. Electron back scatter diffraction (EBSD) analysis revealed that twin activity reoccurred at the same locations after successive cycling. EBSD analysis also showed that residual twins remain in the fine-grained pure Mg condition after 104 cycles.