GB/T 41739-2022Test method for dimensional stability of metal matrix composites—Thermal-cold cycling method (English PDF)

1 Scope

This document specifies the test principle, samples, test devices and test procedure, test results, and test report for real-time detection of the dimensional stability of metal matrix composites using the thermal-cold cycle.

This document applies to the determination for dimensional stability of aluminum matrix composites (thermal-cold cycling temperature range: 20 °C ~ 150 °C), magnesium matrix composites (thermal-cold cycling temperature range: 20 °C ~ 150 °C) and iron matrix composites (thermal-cold cycling temperature range: 20 °C ~ 490 °C).

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB/T 4339, Test methods for thermal expansion characteristic parameters of metallic materials

JC/T 2250, Fused silica

3 Test principle

This document uses a single-push-rod or double-push-rod thermal dilatometer, with the help of a quartz differential component of the same stable material, to measure the length variation of the metal matrix composite at 20 °C before the first cycle and after each thermal-cold cycle (among 15 thermal-cold cycles in total). The push rod transmits the variation in sample length to the sensor, and the shape and size of the push rod shall ensure that the load is applied to the sample.

4 Samples

5 Test devices and test procedure

The requirements for the measuring device for length variation are as follows:

a) The measurement range of length variation shall be 0 mm ~ 2.5 mm, and the resolution shall not be lower than 10-6 mm;

b) Use a constant temperature water bath to keep the temperature of the measuring device for length variation stable; the temperature variation shall not be greater than ±0.5 °C.