Microstructures and Properties of Recycled Composites – Particle Reinforced Iron Matrix Functionally Graded Materials Fabricated by Centrifugal Casting

Abstract

Microstructures and properties of recycled composites ring parts containing cast tungsten carbide particles (CTCp) in a bainitic matrix fabricated from dead or waste composites roll rings by centrifugal casting after remelting treatment, have been tested using SEM, EDS and XRD analyses as well as mechanical property testers. The test results show that the CTCp surface were partially dissolved into the liquid iron at 1650 ºC during remelting. The undissolved CTCp in the Fe melt moved towards the outer region under the action of the centrifugal force during casting, which caused the formation of outer reinforced region and inner unreinforced region along the radial direction of the parts. SEM observation displays that the undissolved CTCp distribution in the outer region is even, and the volume fraction of them is increased with increasing rotational speed of the mold. Besides, mechanical tests of the parts show that the outer region exhibits superior hardness, and the inner region has sufficient impact toughness; the volume fraction of CTCP influences the mechanical properties. The dissolution-reprecipition of CTCP during centrifugal casting was also discussed.