對於金屬材料而言，獲得其成形極限對於模具設計與製程設計相當重要。對於可鍛造性的評估，通常利用圓柱壓縮試驗以得到其成形極限，但對於高延展性之金屬材料，若仍利用圓柱壓縮試驗則不易獲得其成形極限。因此本文將數種凹槽設計應用於圓柱壓縮試驗上，透過不同之凹槽設計改變試件破壞發生之快慢，以利成形極限之獲得。凹槽設計之應力集中效果有助於提早試件破壞的發生，對於找出材料之成形極限極有幫助。而由不同凹槽設計所達到的不同應力集中效果，可改變試件上局部位置能量累積之速度，使試件在不同的壓縮量下發生破壞。此外，具凹槽設計之試件在相同壓縮量下，其能量累積值均比無凹槽試件之能量累積值高，代表凹槽設計的確有加速能量累積之效果。最後，本文以能量消耗率(ECR)作為評估因子，進行不同凹槽設計之效能評比，並提出未來可應用之方向與建議。

　　The forgeability of a material is a good indicator when evaluating different materials for industrial use. Normally, upsetting tests can help to create the forming limit diagram (FLD) of a material, which shows the forgeability of a material in various strain paths. Experimental results show that after large deformation, fractures do not occur on a free surface when testing materials with high ductility. Therefore, a notched upsetting test is proposed in this thesis. Applying notch designs on specimens would help to accelerate the fracture initiation. With different notch designs on a specimen, one can obtain different acceleration effects on the specimen. Also, compared to the specimen without notch design, various notch designs on the specimen would lead to different concentration effects on energy consumption. These concepts and results were demonstrated and supported by the results from finite element analysis, and were verified by notched upsetting tests. An indicator called the Energy Consumption Rate (ECR) was proposed for evaluating the effect of notch designs, and it showed good capability for forgeability evaluation.

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