Effects of Build Angle on Additively Manufactured Aluminum Alloy Surface Roughness and Wettability
Effects of Build Angle on Additively Manufactured Aluminum Alloy Surface Roughness and Wettability
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DOI：
10.1115/1.4053608
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发表时间：
2022-08-01
影响因子：
4
通讯作者：
Thompson, Scott M.
中科院分区：
文献类型：
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作者：
Bailey, Christopher M.;Morrow, Jordan A.;Thompson, Scott M.
利用激光粉床熔融(LPBF)技术制造了一系列直径为5 mm、高度固定为5 mm的铝合金(即AlSi10 Mg)支撑柱，其中包含不同的圆角和构筑方向(即与正常表面成0°、10°、20°、30°、40°、50°和60°)，以确定表面粗糙度和水的润湿性效应。从实验中观察到各向异性润湿，部分原因是LPBF工艺产生的表面不均匀。粉末来源的AlSi10 Mg合金通常是疏水的，在0度和60度的构建角下表现出主要的亲水行为，在10度和20度的构建角下表现出疏水和亲水行为的混合，以及在30度、40度和50度构建角下的疏水行为。测量的表面粗糙度Ra从5到36微米不等，并因位置而异。绘制了三维地形图，观察到算术平均高度Sa为15.52-21.71微米；粗糙度的各向异性改变了润湿行为，从而促使了一些亲水行为。为最平滑的表面提供30度和40度的构建角度。对于50度的构建角度，发现表面明显粗糙。这种异常高的粗糙度是由于熔池接触角与周围粉末床具有最大的毛细作用所致。在本研究中，临界熔池接触角接近于构建角，这表明存在一个临界构建角，它会导致显著的熔池润湿行为，并由于芯吸增强和凝固而增加表面粗糙度。
Laser powder bed fusion (LPBF) was utilized to create a series of aluminum alloy (i.e., AlSi10Mg) 5 mm-diameter support pillars with a fixed height of 5 mm containing varying filet angles and build orientations (i.e., 0 deg, 10 deg, 20 deg, 30 deg, 40 deg, 50 deg, and 60 deg from the normal surface) to determine surface roughness and water wettability effects. From experiments, anisotropic wetting was observed due in part to the surface heterogeneity created by the LPBF process. The powder-sourced AlSi10Mg alloy, typically hydrophobic, exhibited primarily hydrophilic behavior for build angles of 0 deg and 60 deg, a mix of hydrophobic and hydrophilic behavior at build angles of 10 deg and 20 deg, and hydrophobic behavior at 30 deg, 40 deg, and 50 deg build angles. Measured surface roughness, Ra, ranged from 5 to 36 mu m and varied based on location. 3D-topography maps were generated, and arithmetic mean heights, Sa, of 15.52-21.71 mu m were observed; the anisotropy of roughness altered the wetting behavior, thereby prompting some hydrophilic behavior. Build angles of 30 deg and 40 deg provided for the smoothest surfaces. A significantly rougher surface was found for the 50 deg build angle. This abnormally high roughness is attributed to the melt pool contact angle having maximal capillarity with the surrounding powder bed. In this study, the critical melt pool contact angle was near equal to the build angle, suggesting that a critical build angle exists, which gives rise to pronounced melt pool wetting behavior and increased surface roughness due to enhanced wicking followed by solidification.