Manufacturers using additive manufacturing to build parts need to know how the complex thermal histories imparted by rapid heating and cooling affect the homogeneity of the microstructure and mechanical properties within their parts. To identify the possible differences for a part built via powder bed fusion, a simulation incorporating superlayers was used to predict the thermal history for a part built by a selective laser melting process. The simulation captured effects of the increasing distance from the substrate as well as the increasing cross-sectional area for the conical geometry of the part, which were meant to exacerbate thermal history discrepancies between layers. The largest thermal gradient difference between layers was 3.7%, and the largest cooling rate difference was about 10%. Grain size and microhardness measurements on the built parts were used to determine whether the microstructure and mechanical properties changed as a function of distance from the substrate and the increasing cross-sectional area. Differences were found to be negligible because the microhardness and grain size were uniform throughout the part in the build direction. The time (8 s) required to recoat the next layer provided enough cooling time to give similar enough thermal histories to fabricate parts with consistent grain size and microhardness in the build direction.

使用增材制造技术制造零件的制造商需要了解快速加热和冷却所传递的复杂热历史如何影响零件内部微结构的均匀性和机械性能。为了确定通过粉末床熔合制造的零件可能存在的差异，使用结合了超层的模拟来预测通过选择性激光熔化工艺制造的零件的热历史。该模拟捕获了与基材的距离增加以及零件的​​圆锥形几何形状增加的横截面积的影响，这意在加剧层之间的热历史差异。层之间的最大热梯度差为3.7％，最大冷却速率差约为10％。使用已构建零件的晶粒尺寸和显微硬度测量值来确定显微结构和机械性能是否随与基材的距离和横截面积的增加而变化。发现差异可以忽略不计，因为在制造方向上整个零件的显微硬度和晶粒尺寸均一。重涂下一层所需的时间（8 s）提供了足够的冷却时间，以产生足够相似的热历史，从而制造出在制造方向上具有一致的晶粒尺寸和显微硬度的零件。发现差异可以忽略不计，因为在制造方向上整个零件的显微硬度和晶粒尺寸均一。重涂下一层所需的时间（8 s）提供了足够的冷却时间，以产生足够相似的热历史，从而制造出在制造方向上具有一致的晶粒尺寸和显微硬度的零件。发现差异可以忽略不计，因为在制造方向上整个零件的显微硬度和晶粒尺寸均一。重涂下一层所需的时间（8 s）提供了足够的冷却时间，以产生足够相似的热历史，从而制造出在制造方向上具有一致的晶粒尺寸和显微硬度的零件。