Modification of eutectic carbide in multi-component white cast iron

• Grant number: 10/17226-3
• Support type: Regular Research Grants
• Duration: February 01, 2011 - July 31, 2013
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal researcher: Mário Boccalini Júnior
• Grantee: Mário Boccalini Júnior
• Home Institution: Instituto de Pesquisas Tecnológicas S/A (IPT). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

The most important cast alloys for the foundry industry have the formation of faceted/non-faceted eutectic during solidification: cast irons (austenite/graphite), white cast irons (austenite/carbide) and Al-Si (alpha/silicon).In the case of austenite/graphite and alpha/silicon eutectics, technologies for liquid metal treatment were developed in order to control the graphite morphology (inoculation, nodulization) and the silicon morphology (modification). This was not the case for the austenite/carbide eutectic, despite playing a decisive role in the performance of the multi-component white cast irons, main alloy series for wear resistant cast parts. Abrasive wear and thermal fatigue are the main degradation modes observed in most of these parts and both are strongly influenced by the morphology and distribution of eutectic carbides.The objective of the present work is to investigate the fundamentals of the formation of austenite/carbide eutectics and to master the parameters controlling the carbide morphology in the multi-component white cast irons, thus establishing the bases of the technology for casting these alloys with engineered microstructure.Using high purity raw material and directional solidification under inert gas atmosphere, the effect of Ce, S and Te additions on eutectic morphology of Fe-V-C and Fe-Cr-C alloys will be investigated. The results will be evaluated through high definition microscopy, microanalysis and EBSD (electron back scattered diffraction). In addition, the effect of those additions on the eutectic liquid/carbide surface energy will be investigated through sessile drop test. (AU)