Effect of the precipitation of secondary phases on the thermal diffusivity and thermal conductivity of Al-4.5Cu alloy

• Published in: Journal of alloys and compounds Vol. 688; pp. 897 - 902
• Main Authors: Choi, S.W., Cho, H.S., Kumai, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2016
• Subjects: Al-4.5Cu alloy; Casting; DSC; Heat treatment; Thermal conductivity; Thermal diffusivity; Casting; Al-4.5Cu alloy; Thermal conductivity; Thermal diffusivity; Heat treatment; DSC
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.07.137

The effect of the precipitation of secondary phases on the thermal properties of Al-4.5Cu alloy (in wt%) after various heat treatments was investigated using a laser flash apparatus (LFA). The alloy samples were solution treated at 535 °C for six hours followed by warm water quenching and then aged in air at 200 °C for different times. The results showed that the thermal diffusivity of the annealed sample increased relative to that of the as-cast sample in the temperature range from 20 to 260 °C. The thermal diffusivity improved as the solute concentration in the α-Al matrix rapidly decreased. The solution treated sample showed lower thermal diffusivity and conductivity than the artificially aged sample. The thermal conductivity of the solution treated sample was 148 W/m·K at 25 °C, but artificial aging treatment increased it to 166 W/m·K at the same temperature. The thermal diffusivity and thermal conductivity increased in the temperature range between 250 and 400 °C. This increase is due to the precipitation of secondary phases. Precipitation of secondary phases occurred as the temperature increased, which we confirmed via DSC analysis. [Display omitted] •The changes in the thermal diffusivity of Al-4.5Cu alloy were investigated using a LFA.•The thermal properties of the Al-4.5Cu alloy showed sensitivity to the thermal history.•The phase transitions due to the heat treatment led to a change of the thermal properties.•The reduction of defects was enhanced the thermal properties of the Al-4.5Cu alloy.