http://scholars.ntou.edu.tw/handle/123456789/4674
標題: | Vacuum Brazing Ti-15-3 with a TiNiNb Braze Alloy | 作者: | Kao, C. S. Leu-Wen Tsay Wang, S. B. Shiue, R. K. |
關鍵字: | brazing;β titanium;electron backscatter diffraction;filler metal;dissolution;joint strength | 公開日期: | 十月-2019 | 卷: | 9 | 期: | 10 | 起(迄)頁: | 1085 | 來源出版物: | Metals | 摘要: | Among all types of brazing fillers, Ti-based fillers show satisfactory joint strengths in brazing titanium alloys. However, the major concern in using such fillers is the formation of Cu/Ni/Ti intermetallic compound(s) in the joint. In this study, a Ti–15–3 alloy was vacuum brazed with a clad Ti–35Ni–25Nb foil. The brazed zone consisted of a Ti2Ni intermetallic compound in a (β-Ti,Nb)-rich matrix for specimen brazing at 1000 °C/600 s. Raising brazing temperature and time resulted in the Ti2Ni dissolving into the (β-Ti,Nb)-rich matrix. For the specimen brazing at 1100 °C/600s, Ti2Ni could only be observed at the grain boundaries of the (β-Ti,Nb)-rich matrix. After further raising it to 1200 °C/600 s, the Ti2Ni intermetallic compound was all dissolved into the (β-Ti,Nb)-rich phase. The average shear strength was significantly raised from 140 (1000 °C/600 s) to 620 MPa (1100 °C/3600 s). Crack initiation/propagation in the brittle Ti2Ni compound with the cleavage fractograph were changed into the Ti–15–3 base metal with a ductile dimple fractograph. The advantage of using Nb in the TiNiNb filler foil was its ability to stabilize β-Ti, and most of the Ni in the braze alloy was dissolved into the β-Ti matrix. The brazed joint could be free of any intermetallic phases with a proper brazing cycle applied, and the joint was suitable for a few harsh applications, e.g., repeated stresses and impact loadings. |
URI: | http://scholars.ntou.edu.tw/handle/123456789/4674 | DOI: | 10.3390/met9101085 |
顯示於: | 光電與材料科技學系 |
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