Abstract

Directed energy deposition is an additive manufacturing technology which usually relies on prototype machines or hybrid systems, assembled with parts from different producers. Because of this lack of standardization, the optimization of the process parameters is often a mandatory step in order to develop an efficient building process. Although, this preliminary phase is usually expensive both in terms of time and cost. The single scan approach allows to drastically reduce deposition time and material usage, as in fact only a stripe per parameters combination is deposited. These specimens can then be investigated, for example in terms of geometrical features (e.g. growth, width) and microstructure to assess the most suitable process window. In this work, Ti-6Al-4V single scans, produced by means of directed energy deposition, corresponding to a total of 50 different parameters combinations, were analyzed, focusing on several geometrical features and relative parameters correlations. Moreover, considering the susceptibility of the material to oxygen pick-up, the necessity of an additional shielding gas system was also evaluated, by comparing the specimens obtained with and without using a supplementary argon flow. A process window, which varies according to the user needs, was found together with a relationship between microstructure and process parameters, in both shielding scenarios.

Graphic Abstract

中文翻译：

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通过定向能量沉积对Ti-6Al-4V进行单次扫描：评估适当工艺窗口的经济有效的方法

摘要

定向能量沉积是一种增材制造技术，通常依赖于原型机或混合系统，并与来自不同生产商的零件组装在一起。由于缺乏标准化，为了开发有效的构建过程，过程参数的优化通常是必需的步骤。虽然，该初步阶段通常在时间和成本上都很昂贵。单次扫描方法可以大大减少沉积时间和材料使用量，因为实际上每个参数组合仅沉积一个条带。然后可以例如根据几何特征（例如，生长，宽度）和微观结构对这些样品进行研究，以评估最合适的工艺窗口。在这项工作中，通过定向能量沉积产生的Ti-6Al-4V单次扫描，对应于总共50个不同参数的组合进行了分析，重点是几个几何特征和相关参数的相关性。此外，考虑到材料对氧气的吸收敏感性，还通过比较在使用和不使用补充氩气的情况下获得的样品，还评估了附加保护气体系统的必要性。在两种屏蔽情况下，都发现了一个根据用户需求而变化的过程窗口以及微结构和过程参数之间的关系。通过比较使用和不使用补充氩气流获得的样品。在两种屏蔽情况下，都发现了一个根据用户需求而变化的过程窗口以及微结构和过程参数之间的关系。通过比较使用和不使用补充氩气流获得的样品。在两种屏蔽情况下，都发现了一个根据用户需求而变化的过程窗口以及微结构和过程参数之间的关系。

图形摘要