• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1273-1274
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• 2006

Chemically pure, hydride/dehydride titanium powders were cold pre-compacted then extruded at $850^{\circ}C$ and $\sim450MPa$ under argon. The extrusions were 100% dense with a narrow band of surface porosity and equiaxed microstructure of similar magnitude to the starting material. The tensile properties of the bars were better than conventionally extruded CP titanium bar product. Outcomes from this study have assisted in the identification of a number of key characteristics important to the extrusion of titanium from pre-compacted CP titanium powders, allowing the elimination of canning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PM processes.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.759-760
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• 2006

Ti-6Al-4V has low specific gravity, high corrosion resistance and superior mechanical properties but it is very difficult to control oxygen content in MIM process. It is necessary to use powders with coarse particle size to decrease oxygen content of powders, so feedstocks with poor fluidity and sintered bodies with lower density are obtained in such cases. Fine titanium hydride-dehydride powders were blended with atomized powders to accomplish higher fluidity and sintered density. Sintered bodies had higher sintered density and mechanical properties equivalent to those of wrought materials by controlling oxygen content less than 0.35mass%.

• Journal of Powder Materials
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• v.16 no.1
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• pp.28-32
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• 2009

The activation temperatures and hydrogen sorption rates of $Ti_{80-X}Zr_{20}V_X$ alloys were evaluated at room temperature. The alloy powders were prepared by arc melting and then hydride-dehydride(HDH) process. The alloy powders were apt to activate by increase of vanadium in Ti-Zr-V alloys. The easy activation was explained in terms of surface oxygen content which decreased with increase of vanadium on Ti-Zr-V alloys.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.464-470
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• 2000

The compacting and sintering behavior of titanium powders containing oxygen in the range of 1980~8450 ppm was examined. The powders were prepared by the hydride-dehydride (HDH) and by the deoxidation by solid state(DOSS) methods. Their compaction density ranged from 69.0% to 62.3% and decreased with the increase in the oxygen content. It was explained by the effect of oxygen on the hardness of powders. Unlike the compaction density, the oxygen content did not affect the apparent density greatly being 90.5$\pm$0.5% after sintering at $1100^{\circ}C$ for 2 hours. Their average grain size was $60\mu\textrm{m}$ and the size and distribution of pores were about the same for all cases. The hardness of sintered samples showed a linear increase with oxygen and could be expressed as VHN(sintered)= 135.5+64.3$\times$$(wt{\%}O_2)$ The exami-nation of fracture surface revealed that the ductile-brittle transition occurs at oxygen contents of 2987~5582 ppm.