Thermal diffusivity and thermal expansion investigations of titanium grade 5

Abstract

The Titanium Grade 5 (Ti-6Al-4V), with density 4.43 g/cm3 at room temperature (RT), was used to test temperature characteristics of the thermal diffusivity and thermal expansion in the temperature range from RT up to 1100 ℃. Two kinds of the NETZSCH laser flash apparatus, i.e. the low temperature LFA 467 and the high temperature LFA 427 were used. As a reference material a sample made of stainless steel A310 provided by NETZSCH, with density 7.83 g/cm3 at RT, was utilized with temperature range from RT to 480 ℃. The reference material was used to determine the thermal conductivity and specific heat by comparative method. The results of the thermal diffusivity tests of the Titanium Grade 5 performed by means of the LFA 467 and the LFA 427 apparatus showed to be consistent to each other. Thermal expansion measurements of the Titanium Grade 5 were carried out applying the NETZSCH dilatometer DIL 402 C. To analyze temperature characteristics of the specific heat and thermal conductivity the thermal expansion of the tested material was taken into account. Test results of the thermal expansion showed that above 800 °C subsequent heating cycles differed from each other. The sample became very fragile after removal it from the device. The cracking effect of the sample may be due to the absorption of gases from the environment, despite the fact that the tests were carried out in an argon environment.