A Comparative Study of Differential Thermal Analysis Method and Metallographic Observation Method for the α+β/β Transformation Temperature of Titanium Alloys

Abstract:

Differential scanning calorimetry (DSC) method and metallographic observation method have been adapted for the measurement of α＋β/β transformation temperatures of α titanium alloy TA7, α＋β titanium alloy TC4 and near β titanium alloy Ti-1023, and the coincidence has been discussed in the present paper. For the TA7 alloy, an obvious endothermic peak which covers a temperature range of about 60 ℃ occurred during α＋β/β transformation. The transformation temperature defined by the peak of first order derivative of the DSC curve was much near the temperature determined by the metallographic observation method. For the alloys TC4 and Ti-1023, on the other hand, only little baseline shifts which cover a temperature range of about 10~15 ℃ was observed during transformation. A better coincidence with the metallographic observation method was achieved for the alloys TC4 and Ti-1023 owing to the much narrow transformation temperature range.