Functionally Graded Al-SiC Composites by Squeeze Infiltration Technique

Abstract

The liquid metal squeeze infiltration technique is used to produce aluminum silicon carbide functionally graded material (FGM) with layers of aluminum alloy and SiC particle-rich composite region. Al FGM was prepared using preforms of varying volume fraction of SiC and infiltrated with Al 2014 alloy. The mechanical properties and thermal characteristics improved as the volume fraction of the reinforcement increased. The structure and characteristics of the functionally graded composites were studied using optical and electron microscopy (SEM-EDS), and it was correlated with the mechanical characteristics evaluated. SiC preform was prepared by porogen burnout technique. As the percentage of SiC increased from 30 to 50%, the thermal expansion values reduced from 22.7 × 10−6/°C to 8.3 × 10−6/°C. The composite of 50% SiC showed the maximum hardness of 206BHN and compression strength of 610 MPa. The infiltrated SiC composites have unique properties due to low weight and excellent strength, thus meeting specific requirements. The squeeze infiltration process for making Al-SiC FGM composites has been discovered to be a viable solution for higher volume fraction reinforcements.