Operando neutron diffraction and imaging

The nSLM (neutron-compatible Selective Laser Melting) system is an advanced experimental setup designed for operando and quasi in situ investigations in additive manufacturing. It features two distinct chambers:

• Processing Chamber: Houses the build plate and laser interaction area.

• Motor Chamber: Contains precise motorized components to ensure accurate positioning and manipulation during experiments.

Key Features:

1. Laser Scanning and Powder Deposition:

• A high-precision 3-axis scanning unit deflects and focuses the laser beam onto the build plate inside the processing chamber.

• A hopper-based recoater deposits a thin, uniform layer of powder for each layer of fabrication.

2. Controlled Atmosphere:

• The processing chamber is flushed with argon gas, maintaining an inert environment during operation.

• Laminar cross-flow of inert gas is ensured through inlet and outlet channels, protecting the powder bed from oxidation and contamination.

3. Customizable Build Plate:

• The build plate has a standard diameter of 20 mm and is modular to accommodate various features and sensors.

• Compatible sensors include acoustic emission detectors, thermocouples, and heating elements, allowing for versatile experimental setups.

4. Precision Stages for Multimodal Measurements:

• A rotation stage with a step size of 0.01° enables tomography scans and diffraction measurements in multiple transverse directions.

• A motorized goniometer stage and linear stage provide high-precision strain measurements along the build direction by tilting the sample up to 90°.

Applications at the Swiss Spallation Neutron Source (SINQ):

The nSLM is specifically designed for cutting-edge neutron-based characterization techniques, including:

• Operando Strain Measurements: Performed in diffraction mode for real-time insights into elastic and thermal strains.

• Operando Neutron Radiography: Visualizes material behavior during processing.

• Operando Polarized Contrast Neutron Imaging: Explores magnetic or structural properties with enhanced contrast.

• Quasi In Situ Tomography: Provides 3D reconstructions of microstructural evolution between processing steps.

• Quasi In Situ Bragg Edge Imaging: Captures crystallographic information, strain and texture with high spatial resolution.