High-temperature phase change material(PCM) Al-Cu alloy is one kind of solar thermal energy storage material which has the best heat storage characteristics

but the study about influence of Cu content on its thermal characteristics has not yet been reported.The thermal characteristics of Al-Cu alloy with Cu content of 7.4%-51.7% including phase change temperature

phase change latent heat

specific heat

thermal diffusivity and thermal conductivity are investigated by differential scanning calorimetry(DSC) and laser flash apparatus(LFA).The internal mechanism of Al-Cu alloy thermophysical properties is also analyzed from the perspective of metallurgical structure.The results indicate that when Cu content is in the range of 7.4%-51.7%

the phase transition temperature of Al-Cu alloy is within 524.4℃ to 645.9℃.With the growth of Cu content

the mass latent heat of Al-Cu alloy decreases and the volume latent heat increases.Al-7.4% Cu has the maximum melting/freezing mass latent heat

which are 339.6 and 343.5 kJ·kg-1 respectively.Al-51.7% Cu has the maximum melting/freezing volumetric latent heat with 1179 and 1143 MJ·m-3

respectively.When the temperature rises from 25℃ to 500℃

the specific heat of Al-Cu alloy keeps increasing.On the other hand

when Cu content rising from 7.4% to 51.7%

the specific heat of Al-Cu alloy decreases.The specific heat of Al-7.4% Cu is 0.85 J·g-1·K-1 at 25℃ and reaches the maximum 1.08 J·g-1·K-1 at 500℃.Besides

the thermal conductivity of Al-Cu alloy decreases with the increase of Cu content

but its thermal conductivity is still as high as 104 W·m-1·K-1 even if Cu content reaches 51.7%.The results reveal that Al-Cu alloy

as high-temperature phase change material

has great potential of application in the field of solar thermal energy storage.