Effect of Zirconium Concentration on High Temperature Cyclic Oxidation Behavior of Fe‐15Cr‐4Al at 1150°C

Abstract

The effect of zirconium (0.2, 0.55, and 1 weight percent) additions to the base alloy, Fe‐15Cr‐4Al, on cyclic oxidation at 1150°C in air was investigated. Each cycle consisted of 1h holding at temperature followed by half an hour air cooling and every alloy was subjected to 32 cycles. The cyclic oxidation was observed to depend on the zirconium concentration. The lowest zirconium concentration (0.2%) imparted the maximum oxidation resistance. For comparison purposes a similar study was carried out for an alloy containing 1% yttrium. This alloy showed the best resistance to cyclic oxidation. SEM, EDAX, and EPMA of the cross sections of oxidized samples were carried out. The formation of nodules was observed in the scale formed on alloys containing zirconium and yttrium. EDAX of the nodules revealed them to be iron rich with small concentrations of zirconium, chromium, and aluminum.