Measurement and Analysis of Phase Transformation Temperature of TC4 Titanium Alloy

The phase transformation temperature was very important to titanium and titanium alloys. Three methods including the calculation method, differential scanning calorimetry and metallographic techniques were employed to calculate and measure the phase transformation temperature of TC4 titanium alloy. The comparison between the three methods indicated that the theory value obtained by the calculation method approaches the true value, because the method required that the content of each element in the TC4 alloy was in a certain range. The value obtained by the differential scanning calorimetry was a little exorbitant, because continuous heating delayed the phase transformation. The phase transformation temperature could be measured accurately by the metallographic technique if more quenching temperatures were chosen. In the metallographic method, the microstructure of samples quenched from different temperatures was observed and the temperature at which the primary α phase disappeared was determined, so that the transformation temperature of the TC4 titanium alloy was determined to be 998 ℃. The reason of the difference of phase transformation temperature between different titanium alloys was discussed.