Effect of heat-treatment time and temperature on microstructure and damping capacity of Fe-7Al-0.5Ti damping alloy

Fe-7Al-0.5Ti damping alloy was developed and it was heat-treated at different temperatures for different times, Its damping capacity was tested by reversal torsion measurement, and its microstructure was observed under optical microscope. The results indicate that its damping capacity is the highest after it is heated at 900 centigrade for 2 hour and water-cooled. Its logarithmic decrement value δ is over 164×10 -3. When the alloy is heated at 900 centigrade for different times, the grain size increased distinctively in 2 hours, and its damping capacity is restored quickly. After that time, the damping capacity decreased slowly. But when the alloy is heated at different temperature for 1 hour, the grain size increases quickly as the temperature is over 900℃. And the damping capacity is the highest at 1100℃, in which the logarithmic decrement is about 95×10 -3.Therefore, it is the microstructure transformation during the recovery and recrystallization what makes the energy barrier lower and are benefit to the domain boundary motion. By this way, the damping capacity is higher.