Research On The Forming Of Al-BN-SiC Composite

ABSTRACT:Al-BN-SiC is a new composite with excellent comprehensive performance which contains high-temperature self-lubricating, high abrasion resistance and high conductivity. On base of Al-graphite composite, it uses BN instead of graphite to improve high-temperature self-lubricating on base of Al-graphite composite and use SiC to improve abrasion resistance of the material. On account of the existing uneven organization, high cost of forming technology, complicated process problem, this research uses the semi-solid casting as the preparation method of Al-BN-SiC. it uses mechanical stirring to prepare semi-solid slurry and conventional casting to prepare Al-BN-SiC composite in which BN and SiC are well-distributed. The main research and results are as follows:(1) Making Al-BN-SiC semi-solid slurry, establishing the relationship model between solid rate and temperature;(2) Using mechanical stirring with single blade to prepare Al-BN-SiC semi-solid slurry, study the relationship between the blade angle β and distributions of BN and SiC particles;(3) To increase the intensity of stirring and strengthen interaction turbulence effect,it uses mechanical stirring with double blade to prepare Al-BN-SiC semi-solid slurry. In this paper, It studies the influence of the stirring condition on the change of flow field, and the flow characteristics are numerical simulated based on CFD, and provides a base for experiment settings;(4) In this paper, it studies the relationship between the blade angles and distributions of BN、SiC particles and define the rational conditions for the distributions of BN、SiC particles.(5) Conducting conventional casting of Al-BN-SiC semi-solid slurry, preparing Al-BN-SiC composite. Establishing the relationship model between solid rate and BN and SiC particles in ingot, determine the realization of BN and SiC particles evenly distributed in the ingot casting conditions.