Thermophysical Property Measurements on Niobium and Titanium by a Microsecond-Resolution Pulse-Heating Technique Using High-Speed Laser Polarimetry and Radiation Thermometry

A microsecond-resolution technique was used to measure the heat of fusion, specific heat capacity, and electrical resistivity of niobium and titanium in the temperature range of 1600 to 3200 and 1500 to 2200 K, respectively. The method is based on rapid resistive self-heating of a wire-shaped specimen by a current pulse from a capacitor–discharge system. Melting of the specimen occurs in approximately 50 ms. Measured quantities are the current through the specimen, the voltage across the specimen, the radiance from the specimen, and its normal spectral emittance, as functions of time. The true temperature of the specimen is computed from the values of the normal spectral emittance and radiance temperature of the specimen at each instant. The latter quantities are measured by means of high-speed laser polarimetry and radiation thermometry, respectively.