本論文以鈹銅C17200-25-1/2H(TD02)作為研究對象，探討在晶粒大小相近下，其寬度、厚度或軋延方向改變時，對於降伏強度及楊氏模數之影響。
研究中以寬度(1.5 mm – 31.0 mm)、厚度(0.05 mm – 0.20 mm)及軋延方向(0° – 90°)作為實驗因子，將實驗規劃分為三個部分。第一部分：相同晶粒大小、厚度及軋延方向下，改變其寬度。第二部分：晶粒大小相近且相同寬度及軋延方向下，改變其厚度。第三部分：晶粒大小相近且相同厚度及寬度下，改變其軋延方向。
實驗結果發現在第一部分之情況下，寬度由31 mm縮減至1.5 mm後，對其降伏強度及楊氏模數並沒有明顯之差異，因此在寬度31 mm至1.5 mm之範圍內無尺寸效應現象產生。在第二部分，試片厚度由0.20 mm縮減至0.05 mm後，其降伏強度並不會隨著厚度減少而降低，因此在此厚度範圍內無尺寸效應現象，而楊氏模數方面，厚度變化亦不會影響其楊氏模數。在第三部分，試片在軋延方向0°時其降伏強度最大，若以0°方向作為比較基準，當45°方向時，其降伏強度降低約3.4 – 11.7％，90°方向時，降伏強度降低約5.1 – 11.0％。楊氏模數方面，在軋延方向45°時其楊氏模數最小，若以0°方向作比較基準，當45°方向時，楊氏模數降低約3.2 – 12.7％，而0°與90°之楊氏模數無顯著差別。

The objective of the research is to study the size effects of Beryllium Copper (C17200-25-1/2H(TD02)) on the yield strength and the Young’s Modulus.Three control factors, width (1.5 mm – 31.0 mm), thickness (0.05 mm – 0.20 mm) and direction of rolling (0° – 90°), are selected in the experiment. By changing one factor and fixing the others, the size effects can be studied.
The experimental results show that the reduction of the width from 31.0 mm to 1.5 mm does not affect the yield strength and the Young’s Modulus. In addition, the reduction of the thickness from 0.20 mm to 0.05 mm does not generate different yield strength, so the size effects are not obvious as well. Lastly, when the angle between the rolling direction and the direction of the specimens in tension is 0°, the maximum yield strength can be obtained. The yield strength decreases 3.4 – 11.7% when the angle is 45° and 5.1 – 11.0% when the angle is 90°. On the other hand, the Young’s Modulus is about the same when the angle is 0° and 90°. It is at the minimum when the angle is 45°.

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