Microstructural investigations on a series of ${\left({\mathrm{Ti}}_{70.5}{\mathrm{Fe}}_{29.5}\right)}_{100-x}{\mathrm{Sn}}_x$ alloys with $x=5$ , 7, and 9 reveal that Sn addition is effective in introducing both structural and spatial heterogeneities in ultrafine eutectic composites stemming from a large temperature difference between two eutectic temperatures upon solidification. The microstructural heterogeneities in these ultrafine eutectic composites strongly enhance the room temperature compressive plasticity up to $\sim 15.7\%$ .

Ductile ${\mathrm{Ti}}_{45}{\mathrm{Cu}}_{40}{\mathrm{Ni}}_{7.5}{\mathrm{Zr}}_5{\mathrm{Sn}}_{2.5}$ and ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_5$ bulk metallic glasses (BMGs) present different work hardening abilities under compression. Microstructural investigations reveal that nanoscale chemical heterogeneities occur throughout the samples. The morphology of the chemically heterogeneous domains in the as-cast ${\mathrm{Ti}}_{45}{\mathrm{Cu}}_{40}{\mathrm{Ni}}_{7.5}{\mathrm{Zr}}_5{\mathrm{Sn}}_{2.5}$ BMG is irregular and significantly interconnected. In contrast, the as-cast ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_5$ BMG exhibits a spherical morphology of the chemically heterogeneous regions. Furthermore, the distribution of the nanoscale chemical heterogeneity is macroscopically inhomogeneous throughout the material. These findings suggest that the different work hardening abilities of the ${\mathrm{Ti}}_{45}{\mathrm{Cu}}_{40}{\mathrm{Ni}}_{7.5}{\mathrm{Zr}}_5{\mathrm{Sn}}_{2.5}$ and ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_5$ BMGs possibly originate from the different morphologies and distributions of the chemically heterogeneous regions.