| 摘要 |
PURPOSE:To obtain Al alloy parts having low coefficient of thermal expansion, high elastic modulus, and also high modulus of specific elasticity by applying hot rolling to a rolled slab of an Al-Si alloy in which Si content, the size of primary-crystal si, and porosity are specified, respectively, while constraining both ends of the slab. CONSTITUTION:A rolled slab consisting of Al alloy containing 13-40wt.% Si, having <=10mu average size of primary-crystal Si, and also having a degree of denseness of <=5% porosity is used. Hot rolling is applied to the above slab while constraining both ends, in the rolling-width direction, of the slab. The effect of low coefficient of expansion is reduced when Si content in the above alloy is <10%, and, when it exceeds 40%, working is made difficult even if any rapid cooling method is adopted. When the average size of primary-crystal Si exceeds 10mu, cracking occurs at the time of rolling. Further, the porosity of the slab is regulated to <=5% in order to prevent cracking at the time of rolling, and both ends of the slab is constrained in order to prevent edge cracks at the time of rolling. |
