Effect of solidification conditions on microstructure of Ni3Al/C composite
Andrzej Janas, Ewa Olejnik, Andrzej Kolbus, Angelika Kmita
Quarterly No. 3, 2011 pages 220-224
DOI:
keywords: solidification, intermetallic phase, aluminides, ”in-situ” composite
abstract The influence of the solidification conditions on the microstructure of an Ni3Al/C composite, i.e. an engineering material in which the role of a lubricating phase, usually performed by reinforcing phases, is played by carbon, has been studied. When proper conditions are observed, a nickel-aluminium alloy composed in 87 wt. % of nickel and in 13 wt. % of aluminium, containing moreover carbon in an amount of 2.5 wt. %, forms in the solidification process a natural Ni3Al/C "in situ" composite. The composite matrix is nickel aluminide characterised by very interesting functional properties, particularly high strength at elevated temperatures. An inspiration to these studies was the surprisingly similar microstructure observed in different types of cast iron and in the fundamentally different, in regard to chemical composition, structure and microstructure, nickel - aluminium alloy. The aim of the present study was to evaluate the effect of the solidification conditions on the shape of the precipitates of graphite particles. The morphologies of the graphite phases were examined and their chemical composition was determined.