Effect of Ti, Nb, Cr and B on structure and mechanical properties of high aluminium cast iron

In this work, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a high-aluminium alloys, and thus improve the production process. The melting conditions employed in this work enabled the formation of a Fe-Al-C liquid solution. Moreover, titanium additions into the liquid allowed the precipitation of TiC. According to this reaction, the extent of carbon removal from the melt is strongly influenced by the amount of Ti additions. Hence, proper titanium levels can result in total removal of carbon from the liquid. Notice from this figure that Ti additions above 4.5%, totally eliminate the undesirable Al4C3 precipitates. Making Cr, Ti, B additions reduces size of FeAl alloys grains. In addition, this work indicates that the high-aluminium cast iron posses high oxidation resistance, exceeding that of high-chromium cast iron and chromium cast steels. Finally, the alloy ductility can be enhanced by additions of dopants such as B and Cr. Hence, additions of 0.03% B and 0.03%B-5% Cr combined with a heat treatment were implemented. As a result, the alloy ductility was significantly improved, where the strain of up to 5.3%, (B alone) or 15% (B-Cr) were obtained.