GB/T 40307-2021 in English

GB/T40307-2021 is my country's first professional standard for neutron diffraction material texture detection, which stipulates the technical requirements for the entire process from sample preparation to data analysis. The standard is applicable to the macroscopic texture characterization of polycrystalline materials such as metals and ceramics.

Sample preparation specifications

The standard stipulates that the sample size should be in the range of 2-20mm cubic, and cylindrical or spherical specimens are preferred. Take aluminum alloy rolled plate as an example:

• Mark the sample coordinate system along the rolling direction (RD), transverse direction (TD), and normal direction (ND)
• Control the cutting amount ≤0.1mm during machining to avoid introducing new texture
• Surface roughness Ra＜1.6μm to reduce diffraction background

Data collection strategy

Determine the number of pole figures collected according to the complexity of the crystal system:

1. Cubic crystal system: Collect three sets of pole figures of {111}, {200}, and {220}
2. Hexagonal crystal system: Need to add {101}, {102} and other crystal plane pole figures
3. Each pole figure measurement grid ≥1000, angular step ≤5°

Laboratory construction requirements

Establishing a neutron texture testing laboratory must meet the following requirements

• Radiation protection meets the requirements of GB18871
• Temperature control accuracy ±2℃/24h
• Foundation vibration <1μm/s

Standard implementation roadmap

1. Equipment verification phase: Use NIST standard sample SRM660a for wavelength calibration
2. Method development phase: Establish pole figure collection templates for each crystal system
3. Application expansion phase: Develop texture-performance correlation model