Facile strategy for preparing puffed wood-based metal composites with low density and enhanced thermal conduction via high-intensity microwave puffing pretreatment

Metallic wood has recently attracted an increasing attention for its excellent mechanical, electrical, and thermal properties. However, existing metallic wood materials are limited in terms of practical application due to their excessive density, rising production costs, and significant energy consumption. In this study, puffed cracks were created as new filling space for low melting point alloy (LMA) material via high-intensity microwave puffing pretreatment. The prepared metallic wood, a puffed wood-based metal composite (PWMC), shows a relatively low density of 1.84 g/cm3 and maximum thermal conductivity of 0.313 W/(m K), representing a 335 % increase compared to puffed wood (PW). LMA appears to have filled in the puffed cracks to form multiple continuous, mutually parallel thermo-conductive strips. The weight percentage gain (WPG) of PWMC was 233 % when the puffed crack area percentage was 16 %. The enhancement of surface average temperature was 31.7 % at a heating temperature of 70 °C. The lightweight, decorative, and thermal conductive PWMC may have a wide array of household applications. •A puffed wood-based metal composite (PWMC) with light weight and enhanced thermal conductivity was prepared.•PWMC shows adensity of 1.84 g/cm3 and maximum thermal conductivity of 0.313 W/(m K), representing a 335 % increase.•PWMC avoids loss of the natural, aesthetically preferable appearance and sensation of the wood.•Low-melting-point alloy played a key role in improving heat transfer performance of PWMC.