Measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V) by a microsecond-resolution transient technique

A microsecond-resolution pulse heating technique was used for the measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V). The method is based on rapid (50- to 100-[mu]s) resistive self-heating of the specimen by a high-current pulse from a capacitor discharge system and measuring, as functions of time, current through the specimen, voltage across the specimen, and radiance of the specimen. Melting of the specimen is manifested by a plateau in the measured radiance. The time integral of the net power absorbed by the specimen during melting yields the heat of fusion. The values obtained for heat of fusion were 272 J[center dot]g[sup [minus]1] (13.0 kJ[center dot]mol[sup [minus]1]) for titanium and 286 J[center dot]g[sup [minus]1] for the alloy 90Ti-6Al-4V, with an estimated maximum uncertainty of [+-]6% in each value. 12 refs., 2 figs., 3 tabs.