The creep behaviour of nickel alloy 718 manufactured by laser powder bed fusion
The creep behaviour of nickel alloy 718 manufactured by laser powder bed fusion
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DOI：
10.1016/j.matdes.2021.109647
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发表时间：
2021-03-25
影响因子：
8.4
通讯作者：
Clare, A. T.
中科院分区：
文献类型：
--
作者：
Sanchez, S.;Gaspard, G.;Clare, A. T.
激光粉末床熔融（LPBF）制造的部件在关键应用中受到性能的限制。LPBF材料存在微观结构缺陷，如晶粒尺寸和形貌不理想，以及宏观异常，如缺乏熔合。这导致LPBF组件在各种机械性能（如很少研究的蠕变）方面的表现低于其变形后的组件。为了了解LPBF合金718的蠕变行为，采用不同的扫描策略制造零件，并在650℃下进行了600 MPa载荷下的构建方向和蠕变测试。热处理使蠕变寿命增加了5倍，证实了其必要性。在蠕变破坏机制中，构造取向和应力状态是决定因素。由于条纹扫描策略中大量激光重叠区域的不利影响，与条纹扫描策略相比，弯曲扫描策略导致蠕变寿命增加58%。在给定的策略下，与变形合金718相比，LPBF的蠕变寿命提高了24%，这表明LPBF具有超越变形材料性能的潜力。作为这项工作的结果，有可能提出高温蠕变应用的构建策略。(C) 2021作者。Elsevier Ltd.出版。
Components manufactured by laser powder bed fusion (LPBF) are limited by their performance for use in critical applications. LPBF materials have microstructural defects, such as suboptimal grain size and morphology, and macroscale anomalies, such as lack of fusion. This results in LPBF components performing below their wrought counterparts for various mechanical properties, such as creep which has seldom been researched. To understand the creep behaviour of LPBF alloy 718, parts were fabricated using different scanning strategies and build orientations and creep tested at 650 degrees C under a 600 MPa load. Heat treatment increased the creep life by a factor of 5, confirming its necessity. The build orientation and stress state were shown to be determining factors in the creep failure mechanisms. The Meander scanning strategy resulted in a 58% increase in creep life compared to the Stripe strategy, due to the detrimental effects of the numerous laser overlapping regions in the Stripe strategy. For a given strategy, a 24% increase in creep life compared to wrought alloy 718 was observed, indicating that LPBF has the potential to surpass wrought material properties. As a result of this work, it is possible to propose build strategies for high temperature creep applications. (C) 2021 The Author(s). Published by Elsevier Ltd.