The Study of Brazing Refractory Metals
Date Issued
2007
Date
2007
Author(s)
Chan, Yu-Cheung
DOI
zh-TW
Abstract
The brazing of tungsten and tantalum using Ti-base, Au-base and Ag-base braze alloys has been extensively studied. Based on the microstructural observation and three-point bending test results, the brazed joint using 40Ti-35Ni-25Nb braze alloy is primarily consists of TiNi, Ti2Ni, Ni-Ta-Ti intermetallics and Ta-rich phases. The specimen brazed at 1350℃ for 600s has the average strength of 586MPa, the highest strength of 625MPa and the lowest strength of 530MPa. Cleavage fracture is extensively observed for most fractured surfaces. For 50Ti-50Ni braze alloy, the brazed joint is primarily consists of Ta-rich, Ni-Ta-Ti, TiNi and Ti2Ni intermetallic phases. The specimen brazed at 1320℃ for 180s shows the average strength of 614MPa, the hightest strength of 725MPa and the lowest strength of 542MPa. Cleavage fracture is extensively observed for most fractrued surfaces. For the 70Au-22Ni-8Pd braze alloy, the brazed joint is mainly consists of Au-rich, Au-Ni-Pd-Ta, Ni-rich, Au2Ta3 and Au-Ni-Ta phases. The specimens brazed at 1040℃ for 180s exhibits the average strength of 393MPa, the highest strength of 454MPa and the lowest strength of 303MPa. Cleavage fracture is extensively observed for most fractured surfaces. For the 68.8Ag-26.7Cu-4.5Ti braze alloy, the braze joint is primarily consists of TiCu, TiCu4, Ti3Cu4, Ag-rich and Cu-rich phases. The specimes brazed at 880℃ for 300s exhibits the average strength of 496MPa, the highest strength of 582MPa and the lowest strength of 403MPa. Cleavage fracture is extensively observed for most fractured surfaces. Brazing tungsten and tantalum using the Ti50Ni50 brazing alloy demonstrates the highest average strength up to 615MPa.
Subjects
硬銲
三點彎曲試驗
劈裂
介金屬相
brazing
three-point bending test
cleavage
intermetallic
Type
thesis
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