Diffusion behaviors and mechanical properties of binary Mg–Ce system

Abstract

In this work, the solid-solid diffusion reaction and growth kinetics of the Mg–Ce system was investigated by diffusion coupling technique. Four intermetallic compounds Mg12Ce, Mg41Ce5, Mg3Ce, MgCe and one solid solution phase δCe were observed in the diffusion zone with the annealing temperature range of 673–823 K. The results shown that the growth process in the diffusion area was dominated by bulk diffusion. The growth constants, integrated diffusion coefficients, growth activation energies and diffusion activation energies of the four intermetallics were calculated based on the thickness of the phases, reaction temperature and annealing time. Mg3Ce has the largest diffusion activation energy. The mechanical properties of the four IMCs were investigated by using nanoindentation characterization technology and first-principles calculations. The nanoindentation tests show that the Mg12Ce phase possessed the largest Young's modulus (66.08 GPa) and hardness (2.14 GPa). The experimental results are consistent with the trend of the calculated results. The obtained diffusion kinetical properties and mechanical properties of the Mg–Ce system provide useful data for the development of new magnesium-rare earth alloys.