Deoxidation and subsequent densification of sintered titanium by Ca deoxidizer

Abstract

In this study, a sintering process involving simultaneous deoxidation and sintering was developed, using the vapor of a deoxidizer (Ca) to produce low-oxygen, high-density titanium. Compared to a series of reference titanium powder samples, the bodies sintered with Ca exposure had an ∼1,400 ppm lower oxygen content, resulting in an ∼2% increase in their density. This appears to be the result of decreased surface oxidation on the titanium, as increased oxidation suppresses densification at high sintering temperatures. The effect of the Ca deoxidizer was a lower oxidation, thereby increasing the sintered density. The Vickers hardness of sintered bodies from both experiments increased from an initial value of ∼249 Hv at 900 °C to ∼286 Hv at 1,400 °C, respectively. Moreover, both experiments revealed a tensile strength of ∼170 MPa at 900 °C that finally increased to ∼218 MPa at 1,400 °C. Meanwhile, the bodies sintered with Ca, the elongation was on average over 1% higher than contrary samples.