| 摘要 |
An aluminium-based alloy comprises 1.5 to 8 mass % of Si, optionally 3-40 mass % of Sn, optionally one or more of Cu, Zn and Mg in a total amount of 0.1 to 6 mass %, optionally one or more of Mn, V, Mo, Cr, Ni, Co and W in a total amount of 0.01 to 3 mass%. 20-60 area % of the silicon grains have a size less than 4 žm and at least 40 area % of the silicon grains have a size of 4-20 žm. When tin is present the desired distribution of silicon grain sizes is obtained by annealing at 350-450 {C for 8-24 hours, thereby spheroidising and coarsening silicon grains present in the tin phase. The spherical silicon grains are substantially unaffected by repeated rolling and annealing whereas acicular silicon grains are crushed and dispersed. In tin-free embodiments, larger silicon grains are obtained by slow cooling. The desired distribution of silicon grain sizes is then obtained by rolling and roll bonding. |
