Establishment of Laser Sintering Technique for Titanium Powder

Miura, Hideshi; Maeda, Hitoshi; Uemura, Makoto; Takemasu, Teruie; Otsu, Masaaki

doi:10.4028/0-87849-419-7.465

Cited by 1 publication

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“…Similar voids were observed in the oxide formed on CP Ti, and which formed a gap between the oxide monolayers. 10) Similar to the fracture mode of the oxide on CP Ti, it is indicated that these voids were the origin of cracks and promoted the development of these cracks during the adhesion test. Therefore, it is suggested that the exfoliation stress became significantly lower than that of 20 mol%Nb.…”

Section: Exfoliation Stress and Cross-sectional Observationsmentioning

confidence: 75%

“…16) The difference in the exfoliation resistances is caused by the microstructure of the oxide. In CP Ti, a multilayered TiO 2 single-phase oxide layer, containing a void layer (gap), is formed 10) and the exfoliation occurs mainly between these layers. On the other hand, the microstructure of the oxide layer of TNTZ is characterized as dense, fine, and uniform.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Nb Addition on Oxide Formation on Ti–xNb Alloys

Ogawa

Miura-Fujiwara

2019

Mater. Trans.

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It had been reported that Ti29Nb13Ta4.6Zr (TNTZ) alloy forms a dense oxide layer by high-temperature oxidation whereas CP Ti forms a multilayered oxide consisted of rutile monolayers and void layer. This morphological change is supposed to be mainly caused by Nb addition in Ti since the dense oxide layer of TNTZ consists of multiple oxide phases, at least with rutile TiO 2 and TiNb 2 O 7 . In this study, hightemperature oxidation at 1273 K for 3.6 ks in the air of TixNb alloys (x = 1, 5, 7, 10, 13, 15, 18, 20, 23, 26, 28, 30 and 32 mol%) was investigated to discuss the effect of Nb addition to Ti on its high-oxidation behavior, and on its oxide microstructure. From the results of the SEM observation, an oxide layer with a void layer was formed on TixNb substrate from 1 mol%Nb up to 10 mol%Nb. However, densification of the oxide layer was confirmed at Ti13Nb. Then, the dense oxide layer was formed up to 32 mol%Nb. XRD results indicated that only rutile-type TiO 2 was identified from 1 mol%Nb up to 10 mol%Nb, then both TiO 2 and TiNb 2 O 7 were formed from 13 mol%Nb to 32 mol%Nb. These results indicate that dense oxide layer formation attributes to phase separation from TiO 2 to TiNb 2 O 7 . Until 10 mol%Nb, the thickness of oxide layer was suppressed by Nb addition, whereas the layer thickness increased with increasing Nb content from 13 mol%Nb. The maximum exfoliation resistance of the oxide layer was obtained at 20 mol%Nb. The results of oxide growth rate at each TixNb alloys suggested that Nb diffusion in Ti may rate-determining process of the dense oxide layer formation. [

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Section: Exfoliation Stress and Cross-sectional Observationsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%