選擇性雷射熔融(SLM)製造屬於積層製造，為新興的重要製程技術之一。對於金屬零件的原型製作或形貌複雜工件的製作，較傳統製程有明顯的加工優勢。本計畫將以具有優異性能且用途廣泛的鎳基超合金Inconel 718為對象，製作SLM試片。進行整合測試與分析，探討製程條件、金相組織、機械性質及破壞機構間之因果關係，並建立適用於此種工件之疲勞壽命評估模式。全程計畫為兩年，第一年探討鎳基超合金Inconel 718選擇性雷射熔融製造之製程最佳化、熱處理條件優化、金相組織及破壞機構。透過單目標及多目標製程最佳化分析方式，得到最佳製程參數組合。第二年探討此種工件的疲勞性質及疲勞壽命評估模式。建立不同應力比值等振幅負荷及變動振幅負荷歷程下之疲勞性質資料、平均應力修正模式，並由實驗結果來驗證在變動負荷下之最佳疲勞壽命評估模式。最後，探討其疲勞裂縫起始及裂縫成長機構。本研究預期可建立Inconel 718合金的 SLM最佳製程參數組合與後熱處理條件，得到此種工件在靜態與動態負荷下之機械性質，解決其疲勞設計上的問題，供未來使用相關製程與材料的人員作參考。研究成果將具學術及應用價值，並可提升鎳基超合金在工業上的應用層次。 ;Selective laser melting (SLM) manufacturing belongs to additive manufacturing and is one of the important emerging process technologies. Obviously, SLM has processing advantages over traditional manufacturing processes in prototyping of metal parts or manufacturing of complex shaped parts. In this project, integrated test and analysis of SLM Inconel 718 specimen will be performed to explore the causal relationship between process condition, microstructure, mechanical property and failure mechanism. Also, it will establish a fatigue life evaluation model for such specimens. This is a two-year project. In the first year, we plan to discuss the process optimization, metallographic structure and failure mechanism of SLM Inconel 718 alloy. The optimal combination of process parameters will be obtained through single objective and multi-objective process optimization analysis. In the second year, we will investigate the fatigue properties and fatigue life evaluation model of SLM Inconel 718 specimen. The mean stress correction model in fatigue analysis will be established. The predicted fatigue life of the specimen under varying amplitude loading will be verified by experiments. This study is expected to establish optimal process parameter combination in SLM process and suitable post-heat treatment conditions for Inconel 718 alloy. We will obtain mechanical properties of the SLM specimens under static and dynamic loads. The proposed fatigue life evaluation model will be helpful for solving the fatigue design issues. The results of this project will be of academic and practical value, and also enhance the industrial application of nickel-based superalloys.
