The anisotropy of the thermal expansion of α-titanium

In order to resolve the discrepancy found in earlier work, the anisotropic thermal expansion of α-titanium has been determined by the X-ray method. If a small range of temperature is used the coefficient of expansion observed along the hexagonal axis (αc) is smaller than that in the basal plane (αa). The nature of the deviation of the α-titanium structure from ideal hexagonal close-packing and the room temperature elastic behaviour of the metal have been shown to be in agreement with the result that αc (5.6 × 10−6. °C−1) is smaller than αa (9.5 × 10−6. °C−1).