2017年
Structure of nitride layer formed on titanium alloy surface by N-2-gas exposure at high temperatures
14TH INTERNATIONAL WORKSHOP ON SLOW POSITRON BEAM TECHNIQUES & APPLICATIONS
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- 巻
- 791
- 号
- 開始ページ
- 11023
- 終了ページ
- 記述言語
- 英語
- 掲載種別
- 研究論文(国際会議プロシーディングス)
- DOI
- 10.1088/1742-6596/791/1/012022
- 出版者・発行元
- IOP PUBLISHING LTD
Nitride treatment is used for hardening of titanium alloy surfaces. In this study, we prepare samples under two different conditions, (1) 810 degrees C, for 600 min, and (2) 850 degrees C, for 720 min. A depth-profile analysis of the surfaces of the samples is conducted through Doppler broadening measurements of positron annihilation gamma rays using a slow positron beam. Lager S-parameters are obtained near the surface for all samples. These parameters can be explained by the positron annihilation at the grain boundaries between the nano-grains confirmed by transmission electron microscope images. Furthermore, the variation in the W-parameters near the surface is independent of the variation in S-parameters, thus indicating a depth dependence of the W-parameters on the chemical composition of the precipitate at the grain boundaries, also confirmed by energy dispersive X-ray spectroscopy measurements. Variations in the W-parameters was observed to occur in the deeper regions, indicating that the nitrated layer is thicker in the sample prepared under condition (2) and the increased hardness of the sample surface measured using Vickers Hardness method is likely caused by this thicker nitrated layer.
- リンク情報
- ID情報
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- DOI : 10.1088/1742-6596/791/1/012022
- ISSN : 1742-6588
- Web of Science ID : WOS:000400610500022