STRACTURES AND PROPERTIES OF P/M HOT EXTRUDED TITANIUM MATERIALS

The present paper describes the experimental investigations on the hot extrusion of s ponge, electrolytic and HDH titanium powders. The structures were observed and physcial and mechanical properties of extruded materials were determined. The experimental results show that most of the pores in extruded titanium are caused by inclusions in powder The porosity in materials decreases with the increase of extruding reduction ratio.whlile the extruding ratio is up to a given value, the influence of decreasing porosity on the properties of materiais can be neglected. Equiaxed crystal structure was observed when titanium was extruded at above the recrystallization temperature. After annealing coarse grain structure was observed and the impact ductility and the elongation of materials increased. The mechanical properties of titanium depends mainly on the oxygen contens of powder. The strength of material increases with increase of oxyen content, but elongation and impact ductility decrease. The properties of P/M titanium produced by hot extrusion may achieves, or even exceed TAl Standard, if the oxygen content of powder is controlled less than 0.15%.