Magnetic Anisotropy and Cold Worked Texture of Titanium

Magnetic susceptibility determinations have been made for commercially pure titanium metal following various mechanical and thermal treatments. Making use of the known texture of heavily rolled titanium, values have been deduced for the principal susceptibilities and magnetic anisotropy of the hexagonal metallic lattice. The values obtained are: χ|| = 3.340 × 10-6 and χ⊥=3.087 × 10-6 e.m.u. g-1 at 25°C. These figures have been confirmed by preliminary measurements on an oriented single crystal of titanium. Knowing the magnetic anisotropy it is possible to estimate the texture in a specimen of the cold worked or annealed metal from susceptibility measurements made in three orthogonal directions. This has been done in a number of cases, and the practical use of this aspect of the work is discussed. It is shown from magnetic measurements that heavily compressed titanium has a texture in which the basal planes of the hexagonal lattice are normal to the compression direction. Assuming that a compressed specimen approximates magnetically to single crystal behaviour, the temperature variations of the principal susceptibilities have been determined from 25°C to 300°C. The magnetic anisotropy is found to be temperature independent over this range, and the temperature coefficient of susceptibility, dχ/dT, is 0.0011 × 10-6 e.m.u. g-1 deg-1.