Fabrication of lightweight 3D interpenetrated NiTi@Mg composite with superior bending properties
(1. Institute of Metals, School of Materials Science and Engineering, Changsha University of Science & Technology, Changsha 410004, China;
2. Institute of Advanced Wear & Corrosion Resistance and Functional Materials, Jinan University, Guangzhou 510632, China;
3. State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400044, China;
4. Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou 510632, China)
2. Institute of Advanced Wear & Corrosion Resistance and Functional Materials, Jinan University, Guangzhou 510632, China;
3. State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400044, China;
4. Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou 510632, China)
Abstract: A NiTi@Mg interpenetrating phase composite with high strength and lightweight was prepared by additive manufacturing (AM) and infiltration technology, and the interface bonding, three-point bending properties and cyclic compressive properties of NiTi@Mg composites were investigated. The results show that the metallurgically bonded interface is formed at the NiTi/Mg interfaces. The bending strength and compressive strength of the NiTi@Mg composite are 2.5 and 1.7 times higher than those of the NiTi scaffold, respectively. During the bending deformation process, a large number of dislocations are observed to accumulate in the soft Mg area at the interface. Furthermore, the finite element model showed that the stress accumulation area, where the bending crack is initiated, is located at the interface of NiTi and Mg. The strengthening mechanism of NiTi@Mg composites is attributed to the twinning strengthening of Mg and heterogeneous structure strengthening.
Key words: metal composites; NiTi@Mg; bending properties; finite element simulation; strengthening mechanism