The effect of processing parameters and material properties on residual forces induced in Laser Powder Bed Fusion (L-PBF)
The effect of processing parameters and material properties on residual forces induced in Laser Powder Bed Fusion (L-PBF)
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DOI：
10.1016/j.addma.2021.102192
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发表时间：
2021-10-01
影响因子：
11
通讯作者：
Patterson, E. A.
中科院分区：
文献类型：
--
作者：
Magana-Carranza, R.;Sutcliffe, C. J.;Patterson, E. A.
在L-PBF工艺过程中，由于激光束引起的大温度梯度和在构建部件时发生的快速冷却速率而产生应力。在这项研究中，发展的力诱导层从L-PBF过程中的热梯度的循环层原位测量使用力传感器设备（FTD）的几个加工参数，包括激光功率和扫描策略在各种金属粉末。研究了三种扫描策略：条纹、曲折和棋盘形，结果表明曲折产生的残余力最小。所有的工艺参数有很强的影响，在L-PBF的残余应变的发展，并且，它被发现，激光功率上的残余力的影响相对较小，超过一个最小的阈值和以上的临界值的点距离上的残余力的影响不大。研究了四种材料：Ti-6Al-4V、Inconel 625、Inconel 718和马氏体时效钢。马氏体时效钢表现出比其他材料低得多的残余力，这可能是由于在这种材料中的低温相变。通过改变L-PBF室中的惰性气氛，提供了马氏体时效钢中这种机制的证据。此外，将马氏体时效钢样品的惰性气体气氛从氩气改变为氮气对力的发展有影响，当在构建过程结束时释放力时，力的发展改变了部件变形的方向。
During the L-PBF process stresses are developed due to the large temperature gradients induced by the laser beam and the fast cooling rates which occur while the part is being built. In this study, the development of forces induced layer by layer from the cycles of thermal gradient during L-PBF are measured in-situ using a Force Transducer Device (FTD) for several processing parameters, including laser power and scanning strategy in various metal powders. Three scan strategies were studied: Stripe, Meander and Chessboard, and the results showed that Meander developed the lowest residual forces. All of the processing parameters had a strong influence on the development of residual strains in L-PBF; and, it was found that the laser power had relatively little effect on the residual forces above a minimum threshold and that above a critical value the point distance had little effect on the residual forces. Four materials were investigated: Ti-6Al-4V, Inconel 625, Inconel 718 and maraging steel. Maraging steel exhibited much lower residual forces than the other materials, which could be due to the low temperature phase transformation in this material. Evidence for this mechanism in the maraging steel was provided by changing the inert atmosphere in the L-PBF chamber. In addition, changing the inert gas atmosphere from argon to nitrogen for the maraging steel samples had an effect on the development of forces which changed the direction of the part deformation when it was released at the end of the build process.