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Lecture

Influence of Nd and La on nanohardness and elastic modulus of extruded Mg10Gd evaluated by nanoindenation

Wednesday (06.11.2019)
10:15 - 10:35
Part of:


Rare Earth elements improve strength, fatigue life, creep resistance and corrosion properties of Mg alloys by solid solution, grain size and texture optimization and precipitation hardening. This study focuses on nanohardness and reduced elastic modulus of Mg10GdxNdxLa to evaluate small-scale material properties. Reliable localized measurements are of great interest for designing new alloys and the nanoindentation technique offers applying tiny loads and very small indentation sizes. Due to its high solubility in Mg, Gd improves strength mostly by solid solution. However, also Mg5Gd phases form an 10 wt % of Gd. It is known that with increasing the amount of Gd, strength and hardness increases. Nd and La are low-solubility alloying element. Especially by adding La, large brittle second phases form. An increase in nanohardness by decreasing grain size and increasing volume fraction of RE-rich precipitates has been found when increasing the amount of alloying elements. This agrees to the microhardness. Nanohardness values depend strongly on the load used and increase with reducing load and indentation depth. All curves show pop-ins. This onset of plasticity depends on the alloy. The reduced elastic modulus evaluated from nanoindentation is compared to the dynamic modulus of elasticity. Both methods confirm the general trend, that adding of Nd increases the modulus. However, the Young’s Modulus obtained from conventional tensile tests differs.

Speaker:
Prof. Dr. Petra Maier
Hochschule Stralsund
Additional Authors:
  • Prof. Dr. Asta Richter
    TH Wildau
  • Martin Wolff
    Helmholtz Zentrum Geesthacht
  • Dr. Norbert Hort
    Helmholtz Zentrum Geesthacht

Dateien

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Short Paper Version 1 This is the short paper to my lecture. 559 KB Download