High Temperature Oxidation Behavior of Ti811 Alloy
The oxide scale of Ti811 alloy sheet in static air at 700～900 ℃ for different times was investigated by Scanning Electron Microscope(SEM) and Optical Microscope techniques.The influences of oxidation time and temperature on oxidation kinetics of alloys were analyzed.The results show that the isothermal oxidation kinetic curves of composites mainly follow parabolic rate law.When the alloys oxidized at low temperature for short time,the thermodynamic advantage of aluminum is dominant.While the alloys oxidized at high temperature for long time,the thermodynamic advantage of titanium is predominant.The differences among the difference between oxide scale and the metals oxidized and the structures differnce between different layers and the difference of phase structures in the complex mix-type oxidized scales will generate internal stress on the interfaces.When the internal stress reaches the ultimate strength of scales,it will generate cracks and desquamation.