中文摘要：

采用受控扩散凝固技术（CDS）制备A1-18Si合金，研究了液一固混合方式下A1-25Si合金的温度对制备A1-18Si合金组织和性能的影响，探讨了合金的最终凝固组织与耐磨性能和热膨胀性能之间的关系。结果表明，在受控扩散凝固过程中，630℃固态纯Al与850℃液态A1-25Si合金混合所制备的A1-18Si合金中，初生si相分布均匀，形貌规整，晶粒尺寸最小，耐磨性能最好。630℃固态纯A1和900℃液态A1-25Si合金混合制备的A1-18Si合金的线膨胀系数最小（15．51×10℃^-1’）。A1-18Si合金的耐磨性能主要取决于初生si相的平均尺寸、形貌和分布。

英文摘要：

Effects of liquid-solid mixing and mixing temperature of A1-25Si alloy on the microstructure and properties as well as the relationship between microstructure with thermal expansion coefficient and wear resistance of AI-18Si alloy which was prepared by CDS （controlled diffusion solidification） were investigated. The results show that during the CDS, the desirable microstructure with uniformly distributed round primary Si phase can be observed with mixed solid pure-A1 at 630 ℃ with liquid A1-25Si at 850 ℃ alloy, and wear resistance of the alloy exhibits desirable. The lower linear expansion coefficient（ 15. 51 × 10-6℃^-1 from 30 ℃ to 300 ℃ ） of the AI-18Si alloy can be achieved by the mixing of pure-A1 at 630 ℃ and liquid A1-25Si at 900 ℃. The wear resistance of Al-18 alloy Si is mainly dependent on the size , morphology and distribution of primary silicon.