Comparative study on the effect of Nb/Mo alloying on the oxidation behavior of Ti42Al5Mn alloy
Pengxiang Zhao, Yingche Ma, Weiwei Xing, Hui Ma, Kui Liu
Abstract
The oxidation behavior of Ti42Al5Mn0.5Nb, Ti42Al5Mn0.8Nb, Ti42Al5Mn0.5Mo, and Ti42Al5Mn0.8Mo alloys (in at%) was investigated at 800 °C. In the Nb-containing alloys, the oxide scale exhibits a multi-layered structure with TiO 2 layer/Al 2 O 3 layer/TiO 2 -rich layer from the outside to the inside, and the intermediate layer at the oxide-substrate interface remained composed of Laves/Z phase until 1000 h of oxidation. The oxide scale of the Mo-containing alloys was incorporated with a thick mixed layer and is highly susceptible to cracking, the intermediate layer changed from Laves/Z phase to Laves/Z/β o phase with prolonged oxidation. While Nb increases the oxidation resistance of the alloy, a higher Mo content led to an increased oxidation mass gain and exfoliation of the oxide scale.