In this step, you define the source of your materials using the Engineering Data repository for material properties. The Engineering Data workspace is designed to allow you to create, save, and retrieve material models, as well as to create libraries of data that can be saved and used in subsequent projects and by other users.
We recommend using temperature-dependent properties covering the range from room temperature to melt temperature. For the thermal analysis portion of an LPBF Thermal-Structural simulation, the properties required are thermal conductivity, density, and specific heat, and melting temperature must be defined for the material. For the structural analysis we require Young’s Modulus, Poisson’s Ratio, coefficient of thermal expansion, and a plasticity model, such as bilinear isotropic hardening (BISO). For an AM LPBF Inherent Strain simulation, both bilinear isotropic hardening (BISO) and multilinear isotropic hardening (MISO) plasticity models are supported.
The following popular materials for AM are provided as Ansys predefined samples in the Additive Materials library portion of the Engineering Data repository:
17-4PH Stainless Steel
316 Stainless Steel
AlF357
AlSi10Mg
Co-Cr
Inconel 625
Inconel 718
Ti-6AI-4V
The Ansys predefined materials are defined with bilinear isotropic hardening (BISO) plasticity models.
All of the Ansys AM sample materials have creep properties defined. Use creep properties as the mechanism for stress relief when simulating heat treatment to achieve more realistic residual stress relief effects.
Note: The material properties used to generate thermal (loading) strains are not customizable when using Machine Learning Thermal Strain as your chosen strain definition for LPBF Inherent Strain simulations, as specific materials were used to train the ML model. In particular, the materials used to train the model are the same as those validated for thermal simulations in the Additive application.
Procedural Steps
Using Ansys Predefined Materials
The sample materials in the Additive Materials library (within the Engineering Data repository) are automatically available when you insert an AM custom system, either AM LPBF Inherent Strain or AM LPBF Thermal-Structural. If you plan to use one of the sample materials without heat treatment, no action is required here and you can move to the next step.
To use creep properties as the mechanism for stress relief in a heat treatment analysis using Ansys predefined materials, unsuppress the creep model in Engineering Data as described in the heat treatment advanced topic.
Using Granta MI's JAHM Curve Data
For information on using a material from the JAHM Curve Data database, see Using JAHM Temperature-Dependent Material Data in AM Simulation. Note that either a Granta Selector or a Granta MI license is required to get access to JAHM datasets.
Using Custom Materials
To add your own custom material, follow the procedures as described in Material Data in the Engineering Data User's Guide. A nominal strength should be provided at the melt temperature, as a near zero modulus and/or yield strength could lead to convergence problems. (Ansys predefined materials take care of this internally.)
For information about defining your own creep model, see Creep Material Models in the Material Reference.