- 期刊
雷射熔覆Inconel 718鎳基超合金之高溫機械性質研究
High Temperature Mechanical Properties of Laser Cladding Inconel 718
摘要
近年來雷射熔覆技術（Laser Cladding）開始應用在積層製造領域，常用於航空或能源產業的渦輪葉片之修補與製造。本研究使用Inconel 718鎳基超合金的粉末，搭配雷射熔覆製程與熱處理參數，控制材料的顯微組織，透過常溫拉伸試驗以及高溫潛變試驗的結果，對應顯微組織的形貌，了解雷射熔覆Inconel 718鎳基超合金的顯微組織對高溫機械性質的影響。實驗結果中，雷射熔覆的材料組織呈現樹枝狀晶，並因為Nb偏析而形成Laves相，經過熱處理後可以消除偏析的Laves相，於基底相中析出Ni_3（Al,Ti）-γ'相與Ni_3Nb-γ＂相之強化相。其中，熔覆材料在常溫下的硬度達498 HV、抗拉與降伏強度分別達1283 MPa、1188 MPa而延伸率為12%，已可與傳統鍛造製程相當；在高溫潛變試驗中，在704℃、448 MPa條件下的潛變壽命為295小時，已經符合傳統製程規範的23小時標準，由組織的分析可以觀察到，雷射熔覆製程參數所造成的缺陷以及熱處理參數的設定，是影響高溫機械性質之主要因素。
並列摘要
In recent years, laser cladding has been applied in additive manufacturing. In the aerospace or energy industry, laser cladding can repair and manufacture turbine blades. Inconel 718 nickel-based superalloy is among the most common materials for making turbine blades. In this study, Inconel 718 nickel-based superalloy powders were laser cladded. With different laser cladding parameters and heat treatment process, the microstructure is modified. The relationship between the laser-clad microstructure and mechanical properties was analyzed. As laser clad, Nb segregated at interdendritic zones and formed Laves phase. After heat treatment, the segregated Laves phase was eliminated, and the strengthening phases, γ' and γ'', precipitate in the matrix. The hardness, tensile strength, and yield strength of laser clade Inconel 718 at room temperature was 498 HV, 1283 MPa, and 1188 MPa, respectively with elongation of 12%. These properties match the mechanical properties of the wrought materials. The creep life of the laser clad Inconel 718 at the 704 °C and 448 MPa condition were 295 hours. The stress rupture life conformed to the criteria of over 23 hours for Inconel 718. It is shown that the laser cladding defects give rise to the difference in mechanical properties and creep life.