Improved Mechanical Properties and Energy Absorption of BCC Lattice Structures with Triply Periodic Minimal Surfaces Fabricated by SLM

Miao Zhao,Guang Fu,Tao Zhang,Fei Liu,David Zhang,Hailun Zhou

doi:10.3390/ma11122411

Abstract

The triply periodic minimal surface (TPMS) method is a novel approach for lattice design in a range of fields, such as impact protection and structural lightweighting. In this paper, we used the TPMS formula to rapidly and accurately generate the most common lattice structure, named the body centered cubic (BCC) structure, with certain volume fractions. TPMS-based and computer aided design (CAD) based BCC lattice structures with volume fractions in the range of 10–30% were fabricated by selective laser melting (SLM) technology with Ti–6Al–4V and subjected to compressive tests. The results demonstrated that local geometric features changed the volume and stress distributions, revealing that the TPMS-based samples were superior to the CAD-based ones, with elastic modulus, yield strength and compression strength increasing in the ranges of 18.9–42.2%, 19.2–29.5%, and 2–36.6%, respectively. The failure mechanism of the TPMS-based samples with a high volume fraction changed to brittle failure observed by scanning electron microscope (SEM), as their struts were more affected by the axial force and fractured on struts. It was also found that the TPMS-based samples have a favorable capacity to absorb energy, particularly with a 30% volume fraction, the energy absorbed up to 50% strain was approximately three times higher than that of the CAD-based sample with an equal volume fraction. Furthermore, the theoretic Gibson–Ashby mode was established in order to predict and design the mechanical properties of the lattice structures. In summary, these results can be used to rapidly create BCC lattice structures with superior compressive properties for engineering applications.

Highlights

Lattice structures, as multifunctional materials, provide a relatively low density accompanied by high strength, energy absorption, and heat conduction capabilities, which have potential applications in the aerospace, automobile, and biomedicine fields [1,2,3,4]
We used the triply periodic minimal surface (TPMS) formula to generate body centered cubic (BCC) lattice structures with volume in the range of 10 to 30% and successfully fabricated them using Selective laser melting (SLM) with Ti–6Al–4V, providing a novel fractions in the range of 10 to 30% and successfully fabricated them using SLM with Ti–6Al–4V, approach for designers to rapidly generate BCC lattice structures with particular unit sizes and volume providing a novel approach for designers to rapidly generate BCC lattice structures with particular fractions
Compression tests, theoretic analysis of struts, and scanning electron microscope (SEM) results showed that the struts of unit sizes and volume fractions

Summary

Introduction

As multifunctional materials, provide a relatively low density accompanied by high strength, energy absorption, and heat conduction capabilities, which have potential applications in the aerospace, automobile, and biomedicine fields [1,2,3,4]. Compared to conventional fabrication approaches to produce metallic porous structures, such as melt gas injection [5], investment casting [6], physical vapor deposition [7], and the sheet metal technique [8], SLM technology has a variety of advantages, including efficient material utilization, time-saving capabilities, and manufacturing capabilities for complex structures. This technology has been used to fabricate lattice structures in engineering applications [9,10,11,12]. This state-of-the-art manufacturing technology is giving designers greater freedom to design and optimize the geometry of parts without concerns regarding manufacturability [13]

Objectives

Methods

Results

Conclusion