GB/T 21838.4-2020Metallic materials. Instrumented indentation test for hardness and materials parameters - Part 4: Test method for metallic and non-metallic coatings (English PDF)

1 Scope

This document specifies the instrumented indentation test method for the hardness and material parameters of metallic and non-metallic coatings: It is particularly suitable for nano/display

Thin coating test in the micro range: If the indentation depth is so small relative to the thickness of the cover layer that it can be ignored under any possible circumstances

When the cover layer is regarded as a bulk material due to the influence of the base material, it is not necessary to adopt this document: The test restriction conditions in this case will be

The file is given:

This method is limited to the single-layer overlay test with vertical indentation on the surface of the sample, but if relative to the size of the indentation, the

If the thickness or gradient is greater than the measurement resolution, the properties of materials with gradients and multilayer coatings can also be measured on its cross section:

This method does not limit the type of material, it is suitable for metal and non-metal covering layers: In this document, the term "overlay" is used to describe

Connect any solid layers with different substrates and uniform properties: This method assumes that the performance of the overlay does not change with the indentation depth: For composite materials

If the microstructure size is smaller than the indentation size, the composite cover can be regarded as uniform:

This document only applies to the use of a pyramid or conical indenter with a sufficiently small radius of curvature at the tip to ensure the plastic deformation caused by the measurement:

Born inside the cover: For viscoelastic or creep-prone materials, the test time has a great influence on the hardness measurement:

Note 1: ISO 14577-1, ISO 14577-2 and ISO 14577-3 specify the instrumented indentation test method for bulk materials in all force and displacement ranges:

Note 2: The analysis used here does not consider the pile-up or sink-in of the indentation: Use atomic force microscope (AFM) to evaluate the shape of indentation

In order to determine the bumps or depressions on the surface around the indentation, these surface effects cause the underestimation (protrusion) or overestimation (depression) of the contact area in the analysis, and then the

Can affect the measurement results: Bumping usually occurs on fully work hardened materials: Due to the constraint of stress in the plastic deformation zone of the covering layer, the soft extension

The thin covering layer material with good performance is easier to form bumps: The literature shows that when measuring the hardness, the bump will cause the increase of the actual contact area, and this effect has

The measurement of indentation modulus is not obvious, because the rigidity of the convex part is low [1,2]:

2 Normative references

The contents of the following documents constitute indispensable clauses of this document through normative references in the text: Among them, dated quotations

Only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to

This document:

GB/T 21838:1-2019 Instrumental indentation test for hardness and material parameters of metallic materials-Part 1: Test method (ISO 14577-1:2015, IDT)

ISO 14577-2:2015 Instrumental indentation test for hardness and material parameters of metallic materials-Part 2: Inspection and summation of testing machines

Calibration (Metalicmaterials-Instrumentedindentationtestforhardnessand materialsparameters-

Part 2:Verificationandcalibrationoftestingmachines)

ISO /IEC Guide 98-3:2008 (GUM:1995) Measurement Uncertainty Part 3: Guidelines for Expression of Measurement Uncertainty

[Uncertaintyofmeasurement-Part 3:Guidetotheexpressionofuncertaintyin measurement (GUM:1995)]

3 Symbols and description

The symbols and descriptions given in Table 1 of GB/T 21838:1-2019 and Table 1 of this document apply to this document:

GB/T 24174 | GB/T 22565.1 | GB/T 24173 | GB/T 21838.5 | GB/T 21838.3 | GB/T 21838.2 | […]