The Compressive Behavior of Porous TC4 Alloy Scaffolds Manufactured by Selective Laser Melting
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ORIGINAL ARTICLE
The Compressive Behavior of Porous TC4 Alloy Scaffolds Manufactured by Selective Laser Melting Pengcheng Huo1 • Zhanyong Zhao1 • Peikang Bai1 • Minjie Liang1 • Haihong Liao1 • Xinlong Yuan1 • Lizheng Zhang1 • Wenbo Du2 • Bing Han3
Received: 17 July 2020 / Accepted: 13 September 2020 / Published online: 22 September 2020 Ó The Indian Institute of Metals - IIM 2020
Abstract Porous TC4 alloy scaffolds with curved struts were fabricated by selective laser melting (SLM), and the compression deformation behavior of the TC4 alloy scaffolds was studied. When the porous scaffold is compressed along the direction of the building, the stress of the porous scaffold first increases sharply with the increase in the strain, then decreases rapidly and finally shows a stepped increasing trend. Combined with the finite element method and uniaxial compression experiments, the shear position of porous scaffold takes precedence over other parts, and the fracture mainly occurs on the strut near the joint of the porous scaffold. The fracture surface analysis shows that the joint is a ductile fracture, and there is a shallow ‘‘dimple’’ pattern of shear or tear type on the fracture surface, while the fracture morphology of the strut near the joint of porous TC4 alloy scaffold is relatively smooth, which is a typical brittle fracture. The mixed fracture mode is caused by the more concentrated stress at the strut than the joint and the hexagonal close-packed (hcp) fine martensite a0 formed by the SLM. Keywords Porous TC4 alloy scaffolds Curved struts Stress Finite element method Selective laser melting Pengcheng Huo and Zhanyong Zhao have contributed equally to this work. & Peikang Bai [email protected] 1
School of Materials Science and Engineering, North University of China, Taiyuan 030051, China
2
National Key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072, China
3
College of Mechatronics Engineering, North University of China, Taiyuan 030051, China
1 Introduction TC4 alloy has been widely used in medical and other fields because of its excellent mechanical compatibility and biocompatibility (high specific strength and excellent corrosion resistance) [1, 2]. However, the melting point of TC4 is as high as 1668 °C, and there are fewer slip systems in the hexagonal close-packed (hcp) structure [3], which makes the traditional manufacturing technology more and more difficult to meet the rapid manufacturing requirements of TC4 alloy complex precision components. Moreover, the Young’s modulus of the TC4 alloy is around 110 GPa and is much higher than that of human bone (10 to 30 GPa) [4], which cause a ‘‘stress shielding’’ phenomenon between the TC4 alloy implant and the receptor. With the rapid development of advanced forming technology, additive manufacturing technology provides an ideal way to solve the above problems [5–7]. Among them, SLM forming is considered to be the most promising additive manufacturing technology [8–10]. It can be melted point by point, line by line,
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