Microstructural Characterization of TiC–White Cast-Iron Composites Fabricated by In Situ Technique

Abstract

High-chromium white cast-iron specimens locally reinforced with TiC–metal matrix composites were successfully produced via an in situ technique based on combustion synthesis. Powder mixtures of Ti, Al, and graphite were prepared and compressed to fabricate green powder compacts that were inserted into the mold cavity before the casting. The heat of the molten iron causes the ignition of the combustion reaction of the reactant powders, resulting in the formation of the TiC by self-propagating high-temperature synthesis. The microstructure of the resultant composites and the bonding interfaces was characterized by scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructural results showed a good adhesion of the composite, suggesting an effective infiltration of the metal into the inserted compact, yet a non-homogeneous distribution of the TiC in the martensite matrix was observed. Based on the results, the in situ synthesis appears to be a great potential technique for industrial applications.

Preparation and Microstructural Characterization of a High-Cr White Cast Iron Reinforced with WC Particles

“…The composition of the mixture was selected from data the literature. [40]). A cross-section of the specimen was cut by wire electrical discharge for visual control of the inner zones of the composite and the bonding between the composite and the base metal.…”

“…X-ray diffraction (XRD, Cu Kα radiation, Bruker D8 Discover), with a scanning range (2θ) of 20° to 100°, was used to complement the characterization of the phases. [40]). A cross-section of the specimen was cut by wire electrical discharge for visual control of the inner zones of the composite and the bonding between the composite and the base metal.…”

“…Scheme of the (a) mold with the inserted green compacts and (b) reinforced specimen (adapted from[40]). …”

Production of TiC-MMCs Reinforcements in Cast Ferrous Alloys Using In Situ Methods

“…Many types of powders can be processed by SHS but much of the research on MMCs fabricated using this technique has been focused on the following systems: Ti-C [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ], Ni-Ti-C [ 58 , 59 ], Ni-Ti-B 4 C [ 38 , 60 , 61 ], Fe-Ti-C/Fe-Cr-Ti-C [ 7 , 10 , 20 , 22 , 24 , 48 , 54 , 62 ], Cu-Ti-B 4 C [ 6 , 26 , 41 , 42 , 63 ], Al-Ti-C [ 43 , 64 ] and Al-Ti-B 4 C [ 44 , 65 ]. The studies carried out have contributed to the understanding of the effect of key factors, such as particle size, compaction pressure, and casting temperature on the final microstructure and mechanical properties of the MMCs.…”

“…As evident from the literature review, the first cases of SHS application on cast ferrous alloys are from 2005, and the majority of the applications were developed in steel parts [ 6 , 20 , 22 , 44 , 48 , 58 ], using a pressureless infiltration technique, which is less frequent in cast iron components [ 24 , 53 , 54 , 64 ]. The main findings on using the most common powder systems will be presented in the following five sections.…”