Hf-rich bulk metallic glasses as potential insulating structural material

Highlights: • Zr substitution by Hf in (Hf_xZr_1-x)_52.5Ti₅Cu_17.9Ni_14.6Al₁₀ leads to lower thermal conductivity by around 15%. • The lower thermal conductivity is due to higher electrical resistivity as it represents 90% of the total thermal conductivity. • The low thermal conductivity of Hf-rich alloys leads to lower thermal losses through a higher σ_c/κ performance ratio. Tremendous properties of bulk metallic glasses (BMGs) have led to numerous potential applications in the past few years. An obvious interest has been given to their potential as structural material given their high mechanical properties and their ability to be produced in bulk parts of several millimeters in size. Unlike their crystalline counterparts, they also show very promising insulating properties due to the absence of a periodic lattice. In the present work, the interest of using bulk amorphous metallic alloys as materials combining good structural properties and thermal insulation is discussed. The study of Hf-rich BMGs enables to reduce the thermal losses through a higher σ_c/κ performance ratio and thus shows very good potential for future insulating and structural applications.