- 學位論文
鎂合金AZ31 非恆溫沖壓成形性之研究
A Study of Non-isothermal Stamping Characteristics of AZ-31 Magnesium-Alloy
摘要
鎂合金有強度高、質量輕、耐衝擊等特性，現在大多朝電子產品外殼 發展，由於鎂合金在常溫時塑性變形能力低，不易變形，因此必須升高製程溫度產生新的變形機制。溫間製程有分為恆溫與非恆溫成形，本文研究鎂合金AZ31恆溫與非恆溫製程中圓錐杯成形性之差異，發現在非恆溫製程中有較佳的成形性。利用有限元素模擬探討不同模具如圓杯、方杯在非恆溫製程之成形性，研究不同製程參數在對成形性之影響，但金屬本身材料之限制，模擬使用破裂準則有助於提高其準確性，並將不同參數分析結果與類神經網路結合，建立預測模組探討不同參數下破裂深度與成形力之結果，有助於減少實驗資源浪費，並利用有限元素模擬與類神經網路預測之結果差異，比較其誤差範圍確認預測準確性，其結果發現建立的預測模型有合理的準確性。
並列摘要
Due to its lightweight and high specific strength,magnesium alloy has been widely used for metal shell of electronic products. In this study the formability at non-isothermal of AZ31 magnesium alloy sheets are studied by the conical cup value, the circular cup and the square cup drawing experiments and finite element analysis. Also to confer the validity of experimental dies applied in the square cup drawing experiment. The finite element method and statistical analysis are maneuvered to confer the relationship between significant process parameters, such as radius of punch, radius of die corner, forming temperature,and friction coefficient, and also to confer the validity of experimental dies applied in the Different types of experiment. A finite element-based code is utilized to investigate the material flow characteristics under different process parameters, and the abductive network is then employed to synthesize the data sets obtained from numerical simulations, thus establishing a predictive model.From this model, an optimal blank contour for producing Magnesium the circular cup and the square cup drawing with ear-less can be found. Experiments were carried out with Magnesium sheet blanks at various temperature for some cases, and the results of experiments show good agreement with the FEM calculations.