| Summary: | 碩士 === 國立臺北科技大學 === 技術及職業教育研究所 === 105 === The joints were performed by high-frequency induction brazing using an Ag-based alloy (49Ag-16Cu-23Zn-7.5Mn-4.5Ni, wt.%), and through the process parameters to change to improve the bonding strength, the brazing temperature range: 700°C、720°C、740°C、760°C、780°C、800°C, and brazing holding time: 0.7s~2.0s, the WC rod brazed using breaking test found optimization brazed parameters. We also focused on study of bonding mechanism, microstructural and mechanical characteristics in the joint area by metallography. Using the dynamometer to measure the actual cutting force when WC tool milling, and analysis WC tool broke condition. When WC joint using an Ag-based filler metal, the phase were changed in joint region with the increase of temperature and holding time. Island-like α-Cu solid solution phases widely spread in the filler metal and played a role of dispersion strengthening because of the high hardness. Because of the high affinity between Ni, Co and Fe, α-Cu layers formed at the interfaces and strengthened them. The joint strength increased with widening α-Cu layers. With increasing brazing temperature and holding time, the total area and number of island- like α-Cu phases decreased, contributing to weakening the dispersion strengthening effect. The maximum shear strength of brazed joints have the best bonding strength when brazing at 760°C for 0.7s. and Using the dynamometer measure cutting force when tool milling. If the brazing WC has many defects in joint region, the cutting force measurement value of 103N. The normal WC tool for the cutting force measurement value of 124N. Then the general WC tool its cutting force was measured at 133N.
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