Bending properties of additively manufactured commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs: Effect of surface treatment

Seungjong Lee,Nabeel Ahmad,Kayla Corriveau,Cameron Himel,Daniel F Silva,Nima Shamsaei

doi:10.1016/j.jmbbm.2021.105042

Abstract

Additive manufacturing of metallic materials, a layer-wise manufacturing method, is currently gaining attention in the biomedical industry because of its capability to fabricate complex geometries including customized parts fitting to patient requirements. However, one of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading. This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs based on ASTM International standard for metallic bone plates (ASTM F382). In addition, the effect of post surface treatment methods including single shot-peened (SP), dual shot-peened (DP), and chemically assisted surface enhancement (CASE) on bending fatigue performance was also evaluated. Results indicated that bending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to conventionally manufactured (CM) counterparts; however, the bending strength of AM CPTi LC-DCPs is lower than CM counterparts. While the fatigue strength of as-built AM CPTi LC-DCPs is lower compared to the CM counterparts, AM CPTi LC-DCPs after post surface treatments (SP, DP, and CASE) exhibit statistically comparable fatigue strength to the CM CPTi LC-DCPs.

Highlights

Metal additive manufacturing (AM) is popular because of its unique benefits such as the fabrication of complex geometries and personalized parts [1, 2]
additively manufactured (AM) commercially pure titanium (CPTi) Limited Contact Dynamic Compression Plates (LC-DCPs) with different surface conditions including as-built, single shot-peened, dual shotpeened, and chemically assisted surface enhancement conditions and commercially manufactured (CM) counterparts were mechanically tested based on ASTM International standard for metallic bone plates (ASTM F382)
Bending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to CM counterparts; the bending strength of AM CPTi LC-DCPs is lower than CM counterparts

Summary

Introduction

Metal additive manufacturing (AM) is popular because of its unique benefits such as the fabrication of complex geometries and personalized parts [1, 2]. A few studies have reported the potential of customized AM implants [7–9], there is a need to perform biomechanical comparisons to commercially available constructs to ensure adequate biomechanical properties before extensive use. This is important considering AM titanium (Ti) alloys often exhibit lower mechanical performance as compared to the CM counterparts due to the presence of surface roughness or volumetric defects [10, 11]. One of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LCDCP) constructs.

Methods

Results

Discussion

Conclusion