The objectives of this study are: (1) to verify whether using linear heat input alone is sufficient to predict the resulting microstructure of Ti6Al4V and (2) to demonstrate the potential of single-step process of functionally graded material using powder bed fusion. In laser powder bed fusion, linear heat input is defined as the ratio of laser power to scan speed. It is a key process variable that describes the unit energy input. Therefore, linear heat input has been extensively linked with the resulting microstructure. However, review of existing studies shows that when similar linear heat input was used, a marked difference in mechanical properties exists. Using proportionally changed laser power and scan speed in five zones, functionally graded specimens were fabricated in this study. All other parameters remain the same for these zones. Variation of microstructure and hardness across the five zones were obtained. This implies that linear heat input is not sufficient to determine the resulting microstructure and mechanical properties. The amplitude of laser power and scan speed has an effect on the resulting microstructure, so they need to be separately considered in future studies.

中文翻译：

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激光粉末床熔融增材制造微结构功能梯度Ti6Al4V的一步法

这项研究的目的是：（1）验证仅使用线性热输入是否足以预测Ti6Al4V的微观结构，以及（2）证明使用粉末床熔合功能分级材料的单步工艺的潜力。在激光粉末床熔合中，线性热输入定义为激光功率与扫描速度之比。它是描述单位能量输入的关键过程变量。因此，线性热输入已与所得的微观结构广泛地联系在一起。但是，对现有研究的回顾表明，当使用相似的线性热输入时，机械性能存在明显差异。使用在五个区域中按比例变化的激光功率和扫描速度，在本研究中制造了功能分级的标本。这些区域的所有其他参数保持不变。获得了五个区域的微观结构和硬度的变化。这意味着线性热输入不足以确定所得到的微观结构和机械性能。激光功率的幅度和扫描速度会影响最终的微观结构，因此在以后的研究中需要分别考虑它们。