The formation of the structure of cast composites in different solidification conditions

Purpose: In the research work the result of the reinforcement displacement and solidification analysis for aluminium cast composite with ceramic particles in different solidification conditions have been presented. The results of research on the solidification process for heterophase composite have been shown. Design/methodology/approach: : The solidification process of the AK12/ SiC+C composite suspension in various heat abstraction conditions was recorded using the ThermaCAM™E25 photometer system for temperature control and measurement. The system, equipped with a thermovision camera, LCD display and a laser pointer, was connected to a SPIDER 8 recorder and used to monitor, record and, simultaneously, to visualize the temperature changes which take place during composites’ solidification. The structure analysis for composite casts was performed by means of optical microscopy. Findings: As the research has shown, moulds which abstract heat quickly, like a graphite or permanent mould, ensure obtaining a uniform distribution of ceramic particles in the matrix. A longer time of composite suspension solidification facilitates floatation and segregation of the reinforcing particles. Therefore, application of materials which prolong the solidification process, e.g. a sand mould, enables obtaining a gradient or laminar structure in heterophase composites. Practical implications: The mould’s material changes the nature of composite crystallization. Originality/value: It was found that the has a significant influence on the distribution of heterophase reinforcement in the matrix. By applying an appropriate mould material it is possible to shape the cast structure and the distribution of particles in the cast.