Residual Stress Testing Analytical Service

Overview

Residual stress refers to the stress remaining within a material after external forces have been removed. Conventionally, residual stress is categorized into micro-stress and macro-stress, which exhibit different characteristics in X-ray diffraction (XRD) patterns.

• Micro-stress refers to stress retained within individual grains. Its presence broadens diffraction peaks, and the existence of ultra-micro-stress can further reduce peak intensity. This broadening often overlaps with peak broadening caused by grain refinement, forming a convolution. The magnitude of micro-stress can be determined by analyzing the peak broadening using approximation functions or Fourier transform methods.

• Macro-stress refers to stress present over multiple grains and is considered stress at a macroscopic scale compared to micro-stress. Typically, when referring to residual stress, it implies this macroscopic stress. Macro residual stress (hereafter referred to as residual stress) is reflected in XRD patterns as peak shifts. Under compressive stress, the interplanar spacing decreases, causing diffraction peaks to shift toward higher angles. Conversely, tensile stress increases the interplanar spacing, resulting in peak shifts toward lower angles. By measuring the displacement of diffraction peaks, the residual stress in a sample can be quantified.

Sample Requirements

• Dimensions: The sample should have an edge length greater than 5mm and less than 3cm, with a thickness under 8mm. For other dimensions, please submit a testing request for confirmation.

• XRD Testing: XRD measures macro residual stress. Before residual stress testing, a standard XRD scan must be performed to identify a strong, distinct peak in the spectrum. The crystallographic plane index, 2θ angle, Poisson’s ratio, and elastic modulus of the material must be known.

• For Mixtures: Each phase must meet the above conditions. Residual stress for each phase should be measured and then calculated for the entire sample based on the volume fraction of each phase.

• Sample Preparation: It is preferable to cut the sample manually to avoid introducing external stress.

• Anisotropic Samples: Clearly specify the direction of measurement (e.g., for cold-rolled sheets, residual stress along the fiber direction and perpendicular to it may differ).

• Thin Film Samples: For samples with a substrate, thin films may require grazing incidence XRD for testing.

• Special Requirements: For residual stress delamination tests or specific target material testing, please include special notes.

* The price on our website is for reference only. 

* Note: Data analysis service is not included in the list prices.

Highlights: High Quality Data, Competitive Pricing, Technical Support by Scientists.

Analytical Service Minimum order requirement: $250 per order. A $200 handling fee will be applied if order is below $250.

Please contact sales@msesupplies.com for additional information and instructions on our Analytical Services program. Confirmation of the sample(s) requirements, SDS sheets and additional information is needed prior to processing the Analytical Service order. 

***Please do not ship any samples without authorization from MSE Supplies***