Flow transitions and flow localization in large-strain deformation of magnesium alloy

Date

2016-04-06

Author

Sagapuram, Dinakar
Efe, Mert
Trumble, Kevin P.
Chandrasekar, Srinivasan

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Understanding transitions from homogeneous to localized flow, and mechanisms underlying flow localization, is of paramount importance for deformation processing of magnesium. In this study, a shear based deformation method is utilized for imposing large strains (similar to 1), under controllable strain rates (10-10(5)/s) and temperatures (80-300 degrees C), in order to examine flow patterns in a magnesium alloy. Based on microstructure characterization, deformation twinning is suggested to contribute to the localized flow at temperatures below 200 degrees C and at low strain rates. The transition from the localized to homogeneous flow with increasing temperature is due to reduction in twinning activity, and enhanced strain-rate sensitivity. At constant temperature, an increase in the strain rate decreases the propensity for flow localization. A model is presented for characterizing the maximum uniform strain as a function of temperature and deformation state (simple shear, plane-strain compression). The model incorporates temperature-sensitive microstructural changes and flow properties of magnesium into a classical framework to capture the flow localization phenomena at low temperatures and strain rates.

Subject Keywords

Mechanical Engineering, General Materials Science, Mechanics of Materials, Condensed Matter Physics

URI

https://hdl.handle.net/11511/57633

Collections

Department of Metallurgical and Materials Engineering, Article