TEXTURES IN TITANIUM SHEET AND ITS EFFECTS ON PLASTIC FLOW PROPERTIES,

The anisotropic behavior of polycrystalline material depends upon the variation of properties of single crystals as a function of orientation and the perfection or intensity of the texture. The understanding of such behavior patterns must be related to a knowledge of textural variations and single crystal properties. Hexagonal close-packed metals usually exhibit fairly large anisotropy in the single crystal form and the textures that develop during processing are more intense for this structure. The anisotropic behavior patterns of polycrystalline hexagonal materials are quite large. Textures commonly found in titanium and its alloys can be classified according to processing procedures of the alloy and the mill products. Sheet textures may be described as rotated 0001 textures in which the peak is tilted toward the transverse direction between 30 and 60 degrees. A study of the microstructure and alloy compositional effects shows that beta rolling increases the transverse tilt of the basal poles. The effect of increasing additions of beta stabilizing elements is similar to that of beta rolling. A variety of alloys in sheet form have been tested and the anisotropy of mechanical properties measured. It was discovered that the elastic and plastic flow properties are intimately related. Both of these properties, plus yield strength, can be understood from a knowledge of single crystal properties, assuming that the sheet has a very strong texture. Author