| 摘要: | 本研究是利用超音波輔助放電加工鐵基金屬玻璃，並於放電液體中添加帶有負電性之石墨烯粉末或導電鋁粉，發展創新之放電加工方法，以獲得精密加工成型之技術，並改善放電加工後之表面粗糙度及增進加工之穩定性，研究中探討各種放電加工參數，例如：峰值電流、放電週期時間、超音波功率、導電粉末種類、放電液種類等對於加工鐵基金屬玻璃之各種加工特性影響，加工特性包含表面粗糙度、加工時間及電極損耗程度，並利用XRD進行結晶相鑑定分析及SEM表面微結構和加工區變質層觀察。
在油中進行放電之結果顯示，峰值電流0.8A、放電週期時間100µs、超音波功率2段且添加石墨烯粉末濃度1.0×10-2wt%時加工時間有效縮短12%，峰值電流0.8A、放電週期時間100µs、超音波功率2段且添加鋁粉濃度1.0×10-2wt%時表面粗糙度降低28%。在水中進行放電之結果顯示，峰值電流0.8A、放電週期時間100µs、超音波功率4段且添加鋁粉濃度1.0×10-2wt%時表面粗糙度降低25%。由上述結果可以得知超音波振動輔助放電加工可有效提高放電穩定性，提高加工效率及改善加工後表面粗糙度。
透過XRD相鑑定分析，在無添加導電粉末時放電加工後之工件表面皆有產生結晶相層(C以及Cr23C6相)的現象。而添加導電粉末後可以有效改善表面品質，且表面仍保持無結晶結構之型態。
;This study is the use of ultrasonic-assisted electrical discharge machining(EDM) process on Fe-based metallic glass. The negative graphite powder or conductive aluminum powder were added into the working fluids to develop innovative EDM process for obtaining precision processing technology, improving the surface roughness and enhancing the stability of processing. The processing parameters include peak current, duration time, ultrasonic power, conductive powder type and processing fluid type. After completing the experiments, the quality characteristics such as surface roughness, processing time and electrode wear quantity were also analyzed. XRD was used to analyze the crystallization phase identification. SEM was used to observe the surface microstructure and the metamorphic layer of the processing zone.
The result of EDM experiment in oil shows that the combination of parameters include peak current 0.8A, duration time 100µs, ultrasonic power level 2, and graphene powder concentration 1.0×10-2wt%, the processing time is markedly shortened by 42%. Besides, when the peak current is 0.8A, the duration time is 100µs, the ultrasonic power is level 2 and addition of aluminum powder concentration 1.0×10-2wt%, the surface roughness markedly decreased by 58%. The result of EDM experiment in water shows that the combination of parameters include peak current 0.8A, the duration time 100µs, the ultrasonic power level 4 and the aluminum powder concentration 1.0×10-2wt%, the surface roughness decreases by 80%. The ultrasonic vibration-assisted method can improve the EDM process stability, increase material removal rate and improve surface roughness effectively.
Through XRD phase identification analysis, the surface of the workpiece generated the crystalline phase layer (C and Cr23C6 phase) after EDM processing without conducting powder adding. The surface of the workpiece maintained amorphous material after EDM processing with conducting powder adding. |
