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REVIEW ARTICLE

A Review on Design and Mechanical Properties of

Additively Manufactured NiTi Implants for Orthopedic

Applications

Yintao Zhang , Shokouh Attarilar , Liqiang Wang , Weijie Lu , Junlin Yang , Yuanfei Fu 3*
1,2
1*
1
1*
2*
1 State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong
University, Shanghai 200240, China
2 Department of Pediatric Orthopaedics, Xinhua Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine,
Shanghai 200092, China
3 Ninth People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China
Abstract: NiTi alloy has a wide range of applications as a biomaterial due to its high ductility, low corrosion rate, and favorable
biocompatibility. Although Young’s modulus of NiTi is relatively low, it still needs to be reduced; one of the promising ways
is by introducing porous structure. Traditional manufacturing processes, such as casting, can hardly produce complex porous
structures. Additive manufacturing (AM) is one of the most advanced manufacturing technologies that can solve impurity issues,
and selective laser melting (SLM) is one of the well-known methods. This paper reviews the developments of AM-NiTi with a
particular focus on SLM-NiTi utilization in biomedical applications. Correspondingly, this paper aims to describe the three key
factors, including powder preparation, processing parameters, and gas atmosphere during the overall process of porous NiTi.
The porous structure design is of vital importance, so the unit cell and pore parameters are discussed. The mechanical properties
of SLM-NiTi, such as hardness, compressive strength, tensile strength, fatigue behavior, and damping properties and their
relationship with design parameters are summarized. In the end, it points out the current challenges. Considering the increasing
application of NiTi implants, this review paper may open new frontiers for advanced and modern designs.

Keywords: NiTi; Additive manufacturing; Orthopedic implants; Porous structure; Mechanical properties
*Correspondence to: Liqiang Wang, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai
Jiao Tong University, Shanghai 200240, China; wang_liqiang@sjtu.edu.cn; Weijie Lu, Liqiang Wang, State Key Laboratory of Metal Matrix
Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; luweijie@sjtu.edu.cn; Junlin
Yang, Department of Pediatric Orthopaedics, Xinhua Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, Shanghai 200092,
China; yjunlin@126.com; Yuanfei Fu, Ninth People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China;
fuyuanf@163.com

Received: January 6, 2021; Accepted: March 10, 2021; Published Online: April 15, 2021
Citation: Zhang Y, Attarilar S, Wang L, et al., 2021, A Review on Design and Mechanical Properties of Additively Manufactured
NiTi Implants for Orthopedic Applications. Int J Bioprint, 7(2):340. http://doi.org/10.18063/ijb.v7i2.340

1. Introduction shape recovery, recovery stress, and superelastic strain .
[5]
Therefore, NiTi can be found in various applications,
In recent years, shape memory alloys (SMAs) have
[6]
[5]
been widely used in aerospace and biomedical fields such as actuators , aerospace , orthopedic implants
[6]
[5]
due to their excellent shape memory effect (SME) and and fixtures , couplings and fasteners , electrical safety
[8]
[7]
[7]
superelasticity [1-4] . SMA is a smart material that can devices , microelectromechanical systems , navy ,
[8]
convert thermal energy into mechanical work to achieve sports equipment , surgical instruments , and so on.
[8]
certain mechanical properties [5,6] . Among many SMAs, There are two different phases in SMAs, called
NiTi has the best shape memory properties, including high austenite phase (high-temperature phase) and martensite
© 2021 Zhang Y, et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International
License (http://creativecommons.org/licenses/by-nc/4.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the
original work is properly cited.
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