Microstructure, defects and mechanical behavior of beta-type titanium porous structures manufactured by electron beam melting and selective laser melting
Microstructure, defects and mechanical behavior of beta-type titanium porous structures manufactured by electron beam melting and selective laser melting
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电子束熔炼和选区激光熔炼β型钛多孔结构的显微组织、缺陷和力学行为
DOI：
10.1016/j.actamat.2016.04.029
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发表时间：
2016-07-01
期刊：
影响因子：
9.4
通讯作者：
Zhang, L. C.
中科院分区：
文献类型：
--
作者：
Liu, Y. J.;Li, S. J.;Zhang, L. C.
研究了电子束熔炼（EBM）和选择性激光熔炼（SLM）制备的β型Ti-24 Nb-4 Zr-8 Sn多孔结构的显微组织、缺陷和力学行为的差异。分析了熔池的相组成、尺寸和形状、缺陷的体积和分布，并将其与压缩力学性能和疲劳性能进行了关联。由于不同的粉末床温度，EBM和SLM样品的显微组织分别由α + β相和单相组成。SLM期间较快的冷却速率促进了细β枝晶的形成，这导致与EBM部件（分别为45 +/-1.1MPa和1.34 +/-0.04GPa）相比更高的压缩强度（50 +/-0.9MPa）和更低的杨氏模量（0.95 +/-0.05GPa）。固体支柱内存在的大缺陷可能是锡蒸发的结果。由于激光光斑尺寸较小且冷却速率较快，因此在SLM工艺期间更容易捕获锡蒸汽。这导致缺陷数量增加10倍。这些缺陷对钢的静态性能和低应力水平疲劳强度的影响有限，但在高应力水平下会导致疲劳寿命的降低和变化。(C)2016 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
This study investigates the differences in the microstructure, defects and mechanical behavior of porous structures from a beta-type Ti-24Nb-4Zr-8Sn manufactured by electron beam melting (EBM) and selective laser melting (SLM). The phases, size and shape of melt pool, volume and distribution of defects are analyzed and correlated to the compressive mechanical and fatigue properties. Due to different powder bed temperatures, the microstructure of EBM and SLM samples consists of alpha+beta phases and a single phase, respectively. The faster cooling rate during SLM promotes the formation of fine beta dendrites, which leads to a higher compressive strength (50 +/- 0.9 MPa) and lower Young's Modulus (0.95 +/- 0.05 GPa) in comparison to the EBM parts (45 +/- 1.1 MPa and 1.34 +/- 0.04 GPa respectively). The large defects present within solid strut are likely a result of tin vaporization. The tin vapor is more easily trapped during the SLM process due to a smaller laser spot size and a faster cooling rate. This results in a 10 times increase in the number of defects. These defects have a limited influence on both the static properties and low stresses level fatigue strength, but it causes a reduced and variable fatigue life at high stresses level. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.