- 學位論文
鈦銅合金的顯微組織與腐蝕特性之研究
Microstructure and Corrosion Properties of Ti-Cu Alloys
摘要
本研究以真空感應加熱法包模熔鑄Ti-Cu合金，探討熱處理對合金密度、電阻率、電化學特性、微小硬度及顯微組織之影響。結果顯示，鑄造後的Ti-Cu合金的顯微結構主要以TiCu和Ti3Cu4的層狀結構存在，層狀的Ti3Cu4內含有島狀的Ti4Cu2O（包括Ti顆粒）和少量條狀的Ti2Cu3。Ti-Cu合金的X-ray分析結果發現有γ-TiCu及δ-TiCu的兩種結構出現，且熱處理後的繞射強度會提高。Ti-Cu合金進行熱處理後，於層狀Ti3Cu4和島狀Ti4Cu2O的界面處發現孔穴，而顯微結構分析顯示TiCu和Ti3Cu4之間會形成新的板狀結構。在熱處理後Ti-Cu合金的電阻率顯著增加，平均微硬度值略微下降。電化學結果顯示耐腐蝕性差及腐蝕形態呈現Ti元素為腐蝕起始點或較優先腐蝕的地方，因此腐蝕面呈現多孔狀的Cu結構。
並列摘要
The present study focused on vacuum induction melting and investment casting of Ti-Cu alloy, as well as the influence of heat treatment on alloy density, resistivity, electrochemical behavior, micro-hardness and microstructure. The results indicated that the microstructures of cast Ti-Cu alloy showed lamellar-like structure with the presence of the TiCu and Ti3Cu4. The lamellar-like Ti3Cu4 consisted of island-like Ti4Cu2O (comprise Ti particle) and small amounts of lath-like Ti2Cu3. The X-ray diffraction analysis results of Ti-Cu alloy were identified as γ-TiCu and δ-TiCu, the intensity of the peak increased after heat treatment. The Ti-Cu alloy was heat-treated and then the cavities were found between the interface of lamellar-like Ti3Cu4 and island-like Ti4Cu2O. Analysis of the microstructures showed that new plate-like structure formed between TiCu and Ti3Cu4. In case of the heat treatment, the resistivity of the Ti-Cu alloys was increased significantly, and the average micro-hardness value decreased slightly. The electrochemical results indicated poor corrosion resistance and corrosion morphology showed the Ti element became corrosion sources or priority places; therefore porous copper structures on the outer surface were obtained.