熱處理對Inconel718選擇性雷射熔融工件微觀結構及機械性質之影響

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Title:	熱處理對Inconel718選擇性雷射熔融工件微觀結構及機械性質之影響
Authors:	游佳憲;Yu, Chia-Hsien
Contributors:	機械工程學系
Keywords:	鎳基合金;選擇性雷射熔融;積層製造;熱處理;Nickle-base Alloy;Inconel 718;Selective Laser Melting;Additive Manufacture;Heat Treatment
Date:	2021-07-29
Issue Date:	2021-12-07 13:24:45 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究選用 Inconel 718 鎳基合金為實驗材料，以選擇性雷射熔融(SLM)進行積層製造，製程參數是以田口方法進行最佳化而得。Inconel 718 鎳基合金屬於析出強化型合金，為了強化材料機械性質，以及消除選擇性雷射熔融製程所造成的機械性質異向性，常進行固溶及時效後熱處理。本研究探討不同的固溶及時效熱處理條件對於 Inconel 718選擇性雷射熔融工件的微觀結構及機械性質之影響。研究結果顯示，Inconel 718 SLM 積層製造試片經固溶 980℃ × 1 hr 與雙時效 720℃ × 8 hr + 620℃ × 8 hr 後可得到最佳之抗拉強度 1545 MPa。而當固溶溫度高於 1040℃時，因積層製造所導致的異向性已被消除，在平行堆疊方向與垂直方向之硬度僅相差 0.2%。積層製造後若採用較高的固溶溫度(固溶 1100℃ × 1 hr 及時效 720℃ × 8 hr + 620℃ × 8 hr)，會造成晶粒粗大化，及主要析出強化相 γ"之比例下降，導致材料強度下降，但韌性提高，獲得最佳衝擊能為 71.5 J。若採用較高的時效處理溫度(固溶 1040℃ × 1 hr 及時效 770℃ × 8 hr + 620℃ × 8 hr)，會造成過時效，使得材料強度下降，衝擊能上升。;In this study, Inconel 718 nickel-based alloy was selected as the experimental material and manufactured by selective laser melting (SLM). The process parameters used in this study were optimized by Taguchi method in previous study. Inconel 718 nickel-based alloy is a precipitation hardening alloy. In order to strengthen the material and eliminate anisotropic properties caused by the selective laser melting process, solution and aging heat treatments are often adopted. This study investigated the influence of solution and aging heat treatments on the microstructures and mechanical properties of the Inconel 718 SLM specimens. The results show that the optimal tensile strength of Inconel 718 SLM specimens is 1545 MPa after solution at 980℃ × 1 hr and double aging at 720℃ × 8 hr + 620℃ × 8 hr. When the solution temperature is higher than 1040℃, it is found that the anisotropy of mechanical properties caused by additive manufacturing is eliminated. If higher solution annealing (solution 1100℃ × 1 hr and aging 720℃ × 8 hr + 620℃ × 8 hr) is adopted after additive manufacturing, the grain of the material will be coarsened, and the amount of the precipitated strengthening phase γ" will decrease, which will lead to a decrease in tensile strength. However, due to the coarse grain, the toughness was improved and the optimal impact energy was 71.5 J. If higher aging temperature (solution 1040℃ × 1 hr and aging 770℃ × 8 hr + 620℃ × 8 hr) is applied, the material is over-aged, which leads to a decrease in trength and an increase in impact energy.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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