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Vol.59, No.8, 582 ~ 589, 2021
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| Title |
| Influences of Heat Treatment on the Thermal Diffusivity and Corrosion Characterization of Al-Mg-Si alloy |
| 김유미 Yu-mi Kim , 최세원 Se-weon Choi , 김영찬 Young-chan Kim , 강창석 Chang-seog Kang |
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| Abstract |
| The effect of the heat treatment on the Mg2Si phase in Al-Mg-Si alloy was investigated by a laser flash apparatus (LFA), Differential scanning calorimetry (DSC) and corrosion test. The alloy samples were solution treated at 590 ℃ for a half hour followed by warm water quenching, and then aged in air at 180, 200 and 240 ℃ for 5 hours. The results showed that the corrosion resistance of the solid solution treated sample was more improved than the as cast sample. Aging treatment also helped increase corrosion resistance at room temperature. It is thought that the fine Mg2Si precipitation phase on the grain had a more positive effect on improving corrosion resistance than crystallization of the Mg2Si phase on the grain boundaries. Corrosion rate also decreased with increasing aging treatment. The corrosion rate of AT240 was reduced to 1.16 MPY compared with the AT180 test piece, which had a corrosion rate of 3.79 MRY. The solution treated sample also showed lower thermal diffusivity than the aged samples. The thermal diffusivity increased as the solute concentration of Mg and Si in the a-Al matrix rapidly decreased during aging treatment. On the other hand, the thermal diffusivity of the aged samples, in which precipitation was completed by the aging process, decreased as the temperature rose. The thermal conductivities of all samples were similar near 250 ℃ when the β'' phase and β' precipitation was completed.
(Received February 4, 2021; Accepted May 27, 2021) |
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| Key Words |
| Al-Mg-Si, thermal diffusivity, corrosion, precipitation, dissolution |
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