Design and development of a miniaturized multiaxial test setup for in situ x-ray diffraction experiments

Area of Science:

• Materials Science
• Mechanical Engineering
• Experimental Mechanics

Background:

• Accurate material characterization under multi-axial stress states is crucial for engineering applications.
• Existing testing methods often require larger sample sizes or are limited in the stress states they can replicate.
• Miniature samples offer advantages in material savings and testing efficiency.

Purpose of the Study:

• To develop and validate a novel, stand-alone multi-axial loading test setup for miniature samples.
• To evaluate the setup's capability for uniaxial and biaxial stress states (tension and compression).
• To demonstrate the setup's in situ integration with X-ray diffraction for stress analysis.

Main Methods:

• Development of a custom-built multi-axial loading test apparatus.
• Testing of miniature samples under uniaxial tension, uniaxial compression, in-plane biaxial tension, and biaxial compression.
• Comparison of uniaxial test results with standard geometry tests on a universal testing machine.
• Utilizing digital image correlation (DIC) for full-field strain measurement during biaxial testing.
• Integration of the test setup with a laboratory X-ray diffractometer for in situ stress analysis.

Main Results:

• The custom setup demonstrated good agreement in stress-strain responses for uniaxial tests compared to standard methods.
• Digital image correlation confirmed strain homogeneity in the central gage section during biaxial loading.
• In situ X-ray diffraction measurements showed good agreement with load sensor data, validating stress calculations.
• The developed setup successfully tested miniature samples under diverse multi-axial stress conditions.

Conclusions:

• The novel multi-axial loading test setup is a viable tool for characterizing miniature samples.
• The setup provides accurate and reliable stress-strain data for multiple stress states.
• The integration capability with X-ray diffraction enhances its utility for in situ stress analysis in materials research.