Metallic Phase Change Material's Microstructural Stability Under Repetitive Melting/Solidification Cycles

Metallic phase change materials (mPCMs) have been demonstrated as potential passive cooling solution for pulse power applications. The possibility of integrating a metallic PCM directly on top of a heat source, reducing the thermal resistance between the device and the cooling system, could result in a significant improvement in thermal management for transient applications. However, many thermo-physical properties of these alloys are still unknown; furthermore, their microstructural stability with repetitive melting/solidification cycles is not warrant. In this work, we provide a series of potential mPCMs for thermal management of electronics operating on a wide range of application temperatures, followed by an experimental investigation of microstructural and thermo-physical stability of these materials under repetitive melting solidification cycles. The results of the effect of cyclic thermal loading of theses alloys on the melting behavior and latent heat of fusion are discussed. Thermal stability of 51.0 wt  % In–32.5 wt %Bi–16.5 wt %Sn and 50 wt %Bi–26.7 wt %Pb–13.3 wt %Sn–10 wt %Cd alloys, as potential midtemperature mPCM, has been evaluated. The results suggest that these mPCMs maintain their thermo-physical stability over large periods of thermal cycles.