Development of super rapid nitriding process for titanium alloys

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14121
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Materials/Mechanics of materials
• Research Institution: Keio University
• Principal Investigator: KOMOTORI JUN 慶應義塾大学, 理工学部(矢上), 教授 (30225586)
• Co-Investigator(Kenkyū-buntansha): 曙 紘之 広島大学, 工学研究科, 准教授 (50447215) ; 菊池 将一 静岡大学, 工学部, 准教授 (80581579) ; 森田 辰郎 京都工芸繊維大学, 機械工学系, 教授 (90239658)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 大気圧プラズマ / 高周波誘導加熱 / チタン合金 / 超短時間窒化プロセス

Outline of Final Research Achievements

The effects of gas blow velocity on the surface properties of a Ti-6Al-4V alloy treated by gas blow IH nitriding were studied. The surface microstructure of the treated specimens was characterized using SEM and XRD. Vickers hardness and nanohardness were measured and reciprocating wear tests were carried out. The results showed that the nitriding of a specimen was facilitated by using a smaller gas blow nozzle. Incorporating the smaller nozzle resulted in an increase in gas blow velocity, which in turn increased the IH power and the temperature inside a specimen, thus accelerating the nitrogen diffusion. Moreover, nitriding at a lower treatment temperature （973 K） was achieved by increasing gas blow velocity. The specimen nitrided at a lower temperature with a high gas blow velocity exhibited better wear resistance than the untreated specimen. This process also inhibited trans-formation to an acicular phase, which involves apparent grain coarsening.

Free Research Field

材料工学