Comparing AM Materials
Mechanical Properties of AM Polymers
The charts below compare the tensile mechanics of polymer components made by FFF/FDM, SLA, SLS, and Material Jetting, as well as polymers processed by injection molding (IM) which can be taken as a benchmark for many AM thermoplastics. The data includes fiber-reinforced polymers. The data is color-coded by process, placing your cursor over each point shows the related details including the material, manufacturer, and in some cases the test or printing orientation. For simplicity of viewing, single point values are reported, without indication of statistical variation.
From the charts below, you may note:
- Collectively, AM polymers span a wide range of tensile mechanical behavior, and both thermoplastics and photopolymers (thermosets) can exhibit significant elongation (strain) before failure, but this comes with a tradeoff in strength.
- Fiber-reinforced polymers have the highest modulus and tensile strength of all noted materials; in the comparison here, the strongest commercially available AM polymers are (excluding continuous fiber reinforcement*) are short carbon fiber-reinforced FFF and SLS materials.
- The strength and elongation of AM polymers is close to, yet does not quite meet the standard values for the same polymers processed by IM. This is because process-specific defects, such as surface roughness (in all processes) and weak interlayer adhesion (in FFF/FDM) can lead to premature failure.
- Among thermoplastics, high-performance materials such as ULTEM and PPSF have the highest reported modulus and strength.
- The anisotropy of FFF/FDM parts is noted, and depends on material and printing parameters.
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
In many cases, commercial datasheets for the materials (and many others) represented in the charts can be easily found through an online search with the manufacturer and/or material name. These data sheets contain many other properties of interest, which were not tabulated here.
*The Markforged composite printing technology–which is analogous to FFF but enables continuous fibers to be printed within solid thermoplastic parts–achieves tensile moduli of ~20-50 GPa and tensile strength exceeding 0.5 GPa, depending on the fiber reinforcement material.
For further reading on the mechanical properties of AM polymers, you may consult:
- Ligon, et al. “Polymers for 3D Printing and Customized Additive Manufacturing”, Chemical Reviews, 117:10212−10290, 2017.
- Dizon, et al. “Mechanical Characterization of 3D Printed Polymers”, Additive Manufacturing 20:44-67, 2018.
- Brenken, et al. “Fused Filament Fabrication of Fiber-Reinforced Polymers: A Review”, Additive Manufacturing 21:1-18, 2018.
- Paesano, “Polymeric Additive Manufacturing: Present Status and Future Trends of Materials and Processes”, Boeing Technical Journal, 2016.
Mechanical Properties of AM Metals
In the charts that follow, we provide exemplary data on the elastic (Young’s Modulus), plastic (yield and tensile strength), and fracture (maximum elongation) properties of metals commonly used in AM. The selected alloys: SS316L, Ti6Al4V, SS17-4PH, and Al10SiMg, are a small sample of the materials under investigation using metal AM. This is a small set of the many alloy compositions that can be explored using AM, and the complex space that connects alloy composition and processing parameters to these final properties. Even steels have a diverse library of composition, microstructure, and mechanical characteristics. These four alloy systems are chosen for the data presentation because data on each is available from reliable sources, and the AM properties can be compared to standard values for conventional processes such as casting, forging, and metal injection molding. The goal is for you to explore this data on your own, and make observations as to the relationships between the process, treatment conditions (e.g., annealing or sintering), and properties.
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
Source: MIT
For further reading on the mechanical properties of AM metals, you may consult:
- Lewandowski and Seifi, “Metal Additive Manufacturing: A Review of Mechanical Properties”, Annual Review of Materials Research, 46:151–86, 2016.
- DebRoy, et al. “Additive Manufacturing of Metallic Components–Process, Structure and Properties”, Progress in Materials Science, 92:112-224, 2018.
- Kasperovich and Hausmann, “Improvement of Fatigue Resistance and Ductility of TiAl6V4 Processed by Selective Laser Melting”, Journal of Materials Processing Technology 220:202–214, 2015.