On the formation of A1Si10Mg single tracks and layers in selective laser melting: Microstructure and nano-mechanical properties
On the formation of A1Si10Mg single tracks and layers in selective laser melting: Microstructure and nano-mechanical properties
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DOI：
10.1016/j.jmatprotec.2015.11.016
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发表时间：
2016-04-01
影响因子：
6.3
通讯作者：
Everitt, Nicola M.
中科院分区：
文献类型：
--
作者：
Aboulkhair, Nesma T.;Maskery, Ian;Everitt, Nicola M.
选择性激光熔化（SLM）是一种相对较新的制造技术，可用于加工一系列材料。铝合金是SLM的潜在候选者，但比该技术更常用的钛合金更难加工。这是因为前者的物理性质可能导致最终部件中的高孔隙率。虽然大多数研究到目前为止，铝合金的SLM处理已考虑到发展的承载对象，特别是孔隙率的减少和机械性能的零件，它也是重要的是研究过程中形成的单一轨道。本文研究了改变扫描速度对铝合金熔合线和单道形成的影响，以及它们的重叠形成单层。定义了熔池的几何特征以及连续性和/或不规则性的边界，并显示出对扫描速度的依赖性。观察到锁孔模式熔化优势。扫描轨迹和层是无孔隙的，这表明孔隙随着层积累而形成。研究表明，应避免增加层厚度，因为它会促进缺陷。能量色散X射线（EDX）映射实施比较SLM材料和其铸态对应物中的化学成分分布。观察到合金元素分布均匀的细小组织。纳米压痕和EDX被用来建立一个跨单轨道的熔池和它们的相互关系的化学组成的硬度分布的理解。元素分布产生均匀的高纳米硬度，在SLM材料上没有空间变化。(C)2015 Elsevier B. V.版权所有。
Selective laser melting (SLM) is a relatively new manufacturing technique that can be used to process a range of materials. Aluminum alloys are potential candidates for SLM but are more difficult to process than the titanium alloys more commonly used with this technique. This is because of the former's physical properties that can result in high levels of porosity in the final parts. Although the majority of studies to date into the processing of Al alloys by SLM have considered the development of load bearing objects, in particular porosity reduction and mechanical characterization of the parts, it is also important to study the single tracks formed during the process. This paper studies the effect of changing the scan speed on the formation of fusion lines and single tracks from an Al alloy, as well as their overlap to form a single layer. The geometrical features of the melt pools as well as the boundaries of continuity and/or irregularities were defined and showed dependence on scan speed. Keyhole mode melting domination was observed. The scan tracks and layers were porosity-free suggesting pores to form with layer accumulation. Investigations showed that increasing the layer thickness should be avoided as it promoted defects. Energy dispersive X-ray (EDX) mapping was implemented to compare the chemical composition distribution in the SLM material and its as-cast counterpart. A fine microstructure with homogenous distribution of the alloying elements was observed. Nanoindentation and EDX were used to establish an understanding of the hardness profile across melt pools of single tracks and their interrelation to the chemical composition. The elemental distribution yielded uniform high nano-hardness with no spatial variation across the SLM material. (C) 2015 Elsevier B.V. All rights reserved.