Effects of Scanning Strategy on the Microstructure and Mechanical Properties of Sc-Zr-Modified Al-Mg Alloy Manufactured by Laser Powder Bed Fusion
Effects of Scanning Strategy on the Microstructure and Mechanical Properties of Sc-Zr-Modified Al-Mg Alloy Manufactured by Laser Powder Bed Fusion
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DOI：
10.3390/cryst12101348
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发表时间：
2022-10-01
期刊：
影响因子：
2.7
通讯作者：
Nakano, Takayoshi
中科院分区：
文献类型：
--
作者：
Ekubaru, Yusufu;Gokcekaya, Ozkan;Nakano, Takayoshi
激光粉末床熔融（LPBF）制备的Sc-Zr改性Al-Mg合金（Scalmalloy）具有双峰组织，其包括在热熔池区域的粗晶粒（CG）和沿熔池边界（MPB）的沿着的超细晶粒（UFG）。由于这些微观结构特征，MPB的增加可以增加UFG，从而导致增强的机械性能。然而，LPBF工艺参数，特别是激光扫描策略，对Scalmalloy的组织和力学性能的影响仍然不清楚。在这里，X-和XY-模式的激光扫描策略之间进行了比较研究，具有相同的体积能量，基于熔池配置，晶粒尺寸分布，和沉淀行为。X-扫描表现出上级的机械性能表现出的XY-扫描，归因于较高的体积分数（VF）的UFG。由于MPB的增加，观察到UFG的VF增加，从XY扫描的46%增加到X扫描的56%。因此，X-扫描的拉伸强度高于XY-扫描的拉伸强度。对于X扫描策略获得了最大屈服强度（271.5 +/-2.7MPa），这大约是对于铸造获得的屈服强度的两倍。这项研究的结果表明，Scalmalloy的显微组织和力学性能可以成功地调整激光扫描策略。
Laser powder bed fusion (LPBF)-manufactured Sc-Zr-modified Al-Mg alloy (Scalmalloy) has a bimodal microstructure comprising coarse grains (CGs) in the hot melt pool area and ultrafine grains (UFGs) along the melt pool boundaries (MPBs). Owing to these microstructural features, an increase in the MPBs can increase the UFGs, leading to enhanced mechanical properties. However, the effects of the LPBF process parameters, especially the laser scan strategy, on the microstructure and mechanical properties of Scalmalloy are still unclear. Here, a comparative study was conducted between X- and XY-mode laser scan strategies, with the same volumetric energy, based on the melt pool configuration, grain size distribution, and precipitation behaviors. The X-scan exhibited mechanical properties superior to those exhibited by the XY-scan, attributed to the higher volume fraction (VF) of UFGs. An increase in the VF of UFGs was observed, from 46% for the XY-scan to 56% for the X-scan, owing to an increase in MPBs. Consequently, the tensile strength of the X-scan was higher than that of the XY-scan. The maximum yield strength (271.5 +/- 2.7 MPa) was obtained for the X-scan strategy, which was approximately twice that obtained for casting. The results of this study demonstrate that the microstructure and mechanical properties of Scalmalloy can be successfully tuned by a laser scanning strategy.