Electromagnetic self-encapsulation of carbon fiber reinforced Al matrix composite phase change material for high-temperature thermal energy storage

Abstract

Realizing the effective encapsulation of eutectic Al-Si melt is of paramount significance for developing the Al matrix phase change materials in the high-temperature heat storage field. In this paper, a carbon fiber reinforced Al matrix composite phase change material with a Si-rich◎Si-poor cladding structure ([Cf×Si-rich]◎EAl-Si cPCM) was prepared by controlling the precipitation behavior of primary Si under electromagnetic stirring, which can realize the self-encapsulation of eutectic Al-Si alloy. The thermal and structural properties in steady state and non-steady state of the [Cf×Si-rich]◎EAl-Si cPCMs were systematically investigated. The results show that the [Cf×Si-rich] shell has a high thermal conductivity of 53.3–100.7 W/m·K at 200 °C~500 °C. With the increase of Si content in initial Al-Si melt, the high-temperature damage tolerance of the [Cf×Si-rich]◎EAl-Si40 cPCM prepared by Al-40Si is 62.8% higher than that of the [Cf×Si-rich]◎EAl-Si25 cPCM prepared by Al-25Si, but the heat storage capacity is decreased by 22.7%. The [Cf×Si-rich]◎EAl-Si30 cPCM prepared by Al-30Si melt is considered to have the best comprehensive property. Under the non-steady working condition, the [Cf×Si-rich]◎EAl-Si30 cPCM exhibited excellent structural stability and great phase change characteristics (0.3% fluctuation of the melting latent heat and 1.4% fluctuation of the phase change temperature). This work offers new self-encapsulation strategy for extending the application process of Al matrix PCM to the field of high-temperature thermal energy storage.