Plastic instability and texture modification in extruded Mg-Mn-Nd alloy

Journal of Magnesium and Alloys, vol. 10, pp. 146–159

Abstract

Even though Mg alloys containing Mn and rare earth elements lead to higher ductility and lower yield asymmetry due to the weak texture after extrusion, plastic instability, commonly known as the Portevin–Le Chatelier (PLC) effect, causes unexpected fragility in the service environment. In the present study, the PLC phenomenon and texture development during the deformation of Mg-Mn and Mg-Mn-Nd extruded alloys were investigated under various temperatures and strain rates. The addition of Nd causes not only texture weakening but also severe PLC phenomenon. The PLC phenomenon was significantly affected by the temperatures and the strain rates, which causes a difference in mechanical properties and development of texture. In the conditions of high temperature and low strain rate, the strength increased while the elongation decreased significantly, and obvious PLC phenomenon with severe serration and negative strain rate sensitivity. The initial texture was maintained even after deformation only under severe PLC conditions, and this is due to the restriction of basal slip and suppression of lattice rotation in PLC conditions. The series of results indicate that the PLC phenomenon causes a reduction of formability even at high temperature.

Authors 5

1. Sang Kyu Woo corresponding

   Helmholtz-Zentrum Hereon

   Affiliation as printed

   Magic-Magnesium Innovation Center, Institute for Materials and Process Design, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany

2. Risheng Pei Aachen Institut für Metallkunde und Materialphysik

   RWTH Aachen University

   Affiliation as printed

   Institut für Metallkunde und Materialphysik, RWTH Aachen University, Aachen 52056, Germany

3. Talal Al‐Samman Aachen Institut für Metallkunde und Materialphysik

   RWTH Aachen University

   Affiliation as printed

   Institut für Metallkunde und Materialphysik, RWTH Aachen University, Aachen 52056, Germany

4. Dietmar Letzig

   Helmholtz-Zentrum Hereon

   Affiliation as printed

   Magic-Magnesium Innovation Center, Institute for Materials and Process Design, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany

5. Sangbong Yi corresponding

   Helmholtz-Zentrum Hereon

   Affiliation as printed

   Magic-Magnesium Innovation Center, Institute for Materials and Process Design, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany