离心铸造工艺对Al-12.4Si-7Ti自生复合材料组织与性能的影响

Effects of Centrifugal Casting Process on Structures and Properties of Al-12.4Si-7Ti Composites

采用离心铸造方法在不同工艺条件下制备Al-12.4Si-7Ti复合材料筒状试件,研究不同工艺对复合材料铸件径向微观组织特征的影响,测试了不同工艺条件下成形铸件的硬度及耐磨性能。结果表明:Al-12.4Si-7Ti复合材料铸件由聚集大量自生初生Ti Al Si颗粒的外层和基本不含初生颗粒的内层两层组织构成。随着浇注温度升高,铸件外层复合层的颗粒体积分数与硬度值逐渐增大,体积磨损量逐渐减少。铸件壁厚对自生颗粒的偏聚效果无明显影响。浇注温度越高,合金的凝固时间越长,越有利于形成高体积分数的颗粒偏聚区。

The tubular specimens of Al-12.4Si-7Ti composite were prepared under different process conditions by centrifugal casting. Along the radial direction, the influence of the different process conditions on microstructure characteristics was investigated, and the hardness and wear resistance under different process conditions were tested. The results show that Al-12.4Si-7Ti composite castings consist of a gradient structure including the outer layer with many in-situ primary TiA1Si particles and the inner layer with few particles. With the increase of pouring temperature, the particle volume fractions of the outer layer gradually increase, and the hardness on the zones increases as well, while the wear volume loss of the outer layer gradually reduces. The casting section thickness has no obvious influence on the segregation of the authigenic particles. The higher the pouring temperature is, the longer the solidification time is, and the larger area of high volume fraction particles forms.