The transformation temperature of hafnium

The thermophysical properties of hafnium in the temperature range from 293 to 2000 K

“…Experimental investigations of thermal expansion of hafnium were performed in [6,[14][15][16][17][18][19]. High-temperature investigations, performed using the X-ray technique [14][15][16], made possible the calculation of TCLE of hafnium α for the α-phase in two directions, namely, perpendicular, α ⊥c , and parallel, α ||c , to the c axis, and determine the ratio α ||c /α ⊥c .…”

“…High-temperature investigations, performed using the X-ray technique [14][15][16], made possible the calculation of TCLE of hafnium α for the α-phase in two directions, namely, perpendicular, α ⊥c , and parallel, α ||c , to the c axis, and determine the ratio α ||c /α ⊥c . This ratio increases with temperature in the range of 500-1900 K from 1.4 to 2.0, which is due to the anisotropy of hafnium in the α-phase.…”

“…The values obtained in [6,[14][15][16][17][18][19] were processed simultaneously. For this purpose, the data on the lattice parameters obtained using the X-ray technique [15,16] were converted to TCLE of polycrystalline sample by the formula α p = (2α ⊥c + α ||c )/3.…”

“…In the case of LSM processing, the data of their study were used starting with the temperatures of 286.69 K (eight points). ONUFRIEV et al single-crystal sample [16] ing the temperature dependence of heat capacity. In so doing, for convenience in processing, the experimental data on enthalpy were converted to average heat capacity…”

An ultra-high-vacuum chamber for high-temperature X-ray diffractometry

“…In investigations carried out by Romans, Paasche & Kato (1965) with a commercial high temperature diffractometer attachment, it was found that at 10 -6 torr the ~ to fl transformation temperatures of hafnium increased about 100°C in twenty minutes. When the pressure was raised to 5 × 10 -s torr, the transformation temperature increased another 75°C in about five minutes.…”