本論文使用熱膨脹儀器於溫度25℃、350℃與750℃下，對Ti-7.5Mo合金進行準靜態壓縮試驗，其應變速率為0.001s⁻¹、0.01s⁻¹和1s⁻¹，使用光學顯微鏡(OM)和穿透式電子顯微鏡(TEM)觀察合金內部之微觀結構，結合巨觀與微觀結構之關聯，最後以構成方程式模擬材料變形之趨勢。
巨觀機械性質結果顯示，Ti-7.5Mo 合金於相同溫度條件下，隨著應變速率提升時，塑流應力、加工硬化率、應變速率敏感性係數、理論溫生量皆上升，而熱活化體積、活化能則下降；在相同應變速率條件下，隨溫度上升時，塑流應力、加工硬化率、應變速率敏感性係數及理論溫升量皆下降，而熱活化體積、活化能則上升；但由於溫度350℃,1s⁻¹下發生絕熱現象，故在應變速率敏感性係數、熱活化體積、活化能、溫度敏感性係數之曲線顯示會明顯不同。構成方程式模擬結果可觀察出，Ti-7.5Mo 合金可由Johnson-Cook Model 描述其塑性變形趨勢，但高溫熱軟化效應造成模擬有較為明顯之誤差出現，因此藉由修改J-C Model 修正造成的誤差。
微觀結果方面，高溫淬火可得α''正交晶系，而在光學顯微鏡中可觀察出金相為α''麻田散鐵細針狀。在350℃下發現了β 邊界之出現，且在溫度350℃,應變速率條1s⁻¹條件下，出現絕熱剪切帶，而在750℃下β 相逐漸趨於明顯；在穿透式顯微鏡觀察下可發現，母材至高溫下皆出現雙晶結構，且差排與雙晶也隨著應變速率提升而提升，隨著溫度上升而下降。最後結合差排密度、雙晶密度與塑流應力值、加工硬化力之相依性，進而釐清微觀與巨觀性質之關聯。

In this thesis, the mechanical properties and microstructure of biomedical titanium alloy, Ti-7.5Mo,studied by deformation dilatometer at different temperatures(25℃, 350℃ ,750℃) and strain rates(0.001 s-1、0.01 s-1 and 1 s-1).
The results of macroscopic mechanical properties show that under the same temperature, the plastic flow stress, work hardening rate, strain rate sensitivity coefficient and theoretical temperature rising of Ti-7.5Mo alloy all increase with the increase of strain rate, while thermal activation volume and activation energy decrease ; owever, due to the effect of adiabatic phenomenon appears at the temperature 350℃ and strain rate of 1s⁻¹, the curves of strain rate sensitivity coefficient, thermal activation volume, activation energy and temperature sensitivity coefficient varied with true strain are different as compared with other deformation conditions. The simulation of the constitutive equation shows that the quasi-static deformation behaviour of Ti-7.5Mo alloy can be described by Johnson-Cook model, but there are obvious errors appear in the high temperature due to the thermal softening effect. Therefore, a modified Johnson-Cook model is used for high temperature deformation.
The microscopic results show that α'' orthorhombic can be obtained by quenching, and the metallographic of Ti-7.5Mo can be observed to be acicular α'' martensite by OM. The appearance of β boundary is found at 350℃, and ASB was found at temperature 350℃ and strain rate of 1s⁻¹ to verify the appearance of adiabatic shearing effect and the ASB appears. The TEM observations indicate that the twinning appears from the base metal to high temperature, and the dislocation and twinning also increase with the increase of the strain rate, but decrease when the temperature increases. Finally, the dislocation and twin density are related to the plastic flow stress and the work hardening effects. The relationship between the microscopic and macroscopic properties is determined.

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