Heterogeneous nucleation effect of in situ iron-rich nanoparticles on grain refinement of copper alloy

• Fine and equiaxed grains is obtained in cast Cu-10Sn-2Zn-(1~3)Fe-0.5Co (wt.%) alloys.
• Grain diameter was refined to 30~60 μm in Cu-10Sn-2Zn-(1.5~3)Fe-0.5Co (wt.%) alloys.
• Refinement was induced by heterogeneous nucleation effect of iron-rich nanoparticles.
• The effect is enhanced via increment of Fe content and limited by melt recalescence.
• The study clarifies a potential pathway for fabricating bulk nanostructured alloys.

Grain refinement of casting Cu–10Sn–2Zn–(1–3)Fe–0.5Co (wt%) alloys were characterized under the heterogeneous nucleation effect of in situ iron-rich nanoparticles. Grain size of the alloys decreases sharply with an increase of Fe content (Fe≤1.5 wt%), but levels off with a further increase of Fe content (Fe>1.5 wt%). The heterogeneous nucleation effect is correlated with wettability, spatial distribution and size distribution of the nanoparticles and limited by recalescence of the melt. This work offers a potential pathway for fabricating bulk nanostructured alloys to realize excellent properties by investigating the heterogeneous nucleation effect of in situ precipitation nanoparticles.