Deformation Behavior of Inconel 625 Alloy with TPMS Structure

Area of Science:

• Materials Science and Engineering
• Additive Manufacturing
• Mechanical Engineering

Background:

• Traditional porous structures exhibit limitations like stress concentration and poor adjustability.
• Triply periodic minimal surfaces (TPMS) offer inherent advantages such as smooth, interconnected, and tunable porosity.
• Laser powder bed fusion (LPBF) is an advanced additive manufacturing technique suitable for creating complex lattice structures.

Purpose of the Study:

• To fabricate and evaluate the compressive performance of Inconel 625 TPMS lattice structures with different topologies.
• To compare the energy absorption capabilities and mechanical properties of Primitive, IWP, Diamond, and Gyroid TPMS designs.
• To investigate the influence of porosity on the structural integrity and mechanical response of the fabricated lattices.

Main Methods:

• Fabrication of Inconel 625 TPMS lattice structures using laser powder bed fusion (LPBF).
• Quantification of theoretical vs. fabricated volumes using Archimedes' principle.
• Uniaxial compression testing of samples, validated by numerical simulations.
• Analysis of deformation mechanisms and porosity effects on mechanical performance.

Main Results:

• The IWP lattice topology demonstrated superior yield strength and energy absorption efficiency compared to Primitive, Diamond, and Gyroid.
• The IWP structure exhibited a unique layer-by-layer failure mode, contributing to its enhanced mechanical properties (Yield Strength: 113.16 MPa, Elastic Modulus: 735.76 MPa, Energy Absorption: 9009.39 MJ/m³).
• Porosity significantly influenced the mechanical performance, with 70% and 80% porosity specimens showing distinct responses.

Conclusions:

• The IWP TPMS lattice is a highly effective topology for Inconel 625 components manufactured via LPBF, offering enhanced mechanical performance.
• LPBF-fabricated TPMS structures provide a viable alternative to traditional porous materials, with tunable properties for specific applications.
• Understanding deformation mechanisms and porosity effects is crucial for optimizing the design and application of TPMS lattices.