First experimental measurement of calcium diffusion in magnesium using novel liquid-solid diffusion couples and forward-simulation analysis

Abstract

A novel liquid-solid diffusion couple enables effective measurements of composition profiles at high temperatures. A forward-simulation analysis is then performed to extract both interdiffusion and impurity diffusion coefficients. The combined method enables measurement of the first ever set of impurity diffusion coefficients of Ca in Mg and reliable high-temperature diffusion data of Al in Mg. The results show that Ca diffuses faster than the Mg self-diffusion which is faster than the Al impurity diffusion in Mg; thus Ca may not be an ideal element for the enhancement of high-temperature creep strength of Mg alloys as has been often assumed.