Mechanical properties and microstructural change in (Cu–Fe) immiscible metal matrix composite: Effect of Mg on secondary phase separation

Phase morphology and the distribution of the strengthening phase generally have a strong influence on the movement of dislocations. The presence of minor alloying element Mg in Cu–30Fe alloy significantly affects both the morphology and distribution of the strengthening phase. Dendritic α-Fe is transformed into a spherical morphology because of changes in the chemical composition during the solidification process. The presence of Mg leads to the formation of secondary phase-separated Cu within the α-Fe phase and to increasing heterogeneity of the gradient size of the α-Fe phase. The increased volume fraction of α-Fe enhanced by secondary separated Cu, refinement of α-Fe, and the degree of distribution enhanced the yield strength of this alloy by 40% compared with that of Cu–30Fe. This result can be used as a guide to modifying the morphology of Cu–Fe alloys and improve understanding of strengthening mechanism of this system.