Investigation of effects of process parameters on microstructure and hardness of SLM manufactured SS316L
Investigation of effects of process parameters on microstructure and hardness of SLM manufactured SS316L
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DOI：
10.1016/j.jallcom.2018.01.098
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发表时间：
2018-04-05
影响因子：
6.2
通讯作者：
Hansen, Vidar
中科院分区：
文献类型：
--
作者：
Tucho, Wakshum M.;Lysne, Vidar H.;Hansen, Vidar
气孔是选区激光熔化（SLM）成形零件中威胁其力学性能的主要缺陷之一。因此，优化材料的致密化是SLM以及其他类似方法的关键目标，以根据应用实现所需的性能。在这项研究中，在不锈钢（SS）316 L零件与SLM制造的孔隙率水平进行了研究，在微观结构和材料硬度的工艺参数的影响。所研究的材料是在50-80 J/mm（3）的能量密度范围内制造的，并使用各种表征技术进行了研究。目前的研究证实，能量密度与孔隙率和硬度有很强的关系，它是控制孔隙率和提高材料密度的最有影响力的变量。在50和80 J/mm（3）之间的能量密度的范围内，孔隙率随能量密度的增加几乎呈指数下降，硬度随能量密度的增加呈线性增加。结果与文献中的报道非常一致，并且证明了利用SLM制造SS 316L达到最高密度（>99.8%），并且预测了通过进一步增加能量密度来优化以实现最大密度的可能性。除了奥氏体（γ）之外，用TEM进行的显微组织分析揭示了在SLM制造的SS 316L的奥氏体基质中存在马氏体和/或铁素体的微小结构。(C)2018爱思唯尔B. V.保留所有权利。
Porosity is one of the major defects threatening mechanical properties in parts manufactured with Selected Laser Melting (SLM) method. Optimizing densification of materials is thus a key target of SLM as well as other similar methods to achieve the desired properties as per applications. In this study, porosity levels in Stainless Steel (SS) 316L parts manufactured with SLM were studied in relation to the effects of process parameters on microstructure and material hardness. Materials studied were manufactured in the energy density range of 50-80 J/mm(3) and investigations have been conducted using various characterization techniques. The current study confirmed a strong relationship of energy density with porosity and hardness and it exhibits as the most influential variable that could control porosity and improve density of materials. In the range of energy density between 50 and 80 J/mm(3), porosity decreases nearly exponentially and hardness increases linearly, with increasing energy density. The result is well in agreement with reports in the literature and demonstrates fabrication of SS316L with SLM to a highest density (>99.8%) and predicts possibility of optimization to achieve maximum density by further increasing energy density. In addition to austenite (gamma), the analysis of microstructure with TEM reveals presence of tiny structures of martensite and/or ferrite in the austenite matrix of the SLM-fabricated SS316L. (C) 2018 Elsevier B.V. All rights reserved.