GB/T 41739-2022 English PDF (GBT41739-2022)

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 ¡ãC ~ 150 ¡ãC), magnesium matrix composites (thermal-cold cycling temperature range: 20 ¡ãC ~ 150 ¡ãC) and iron matrix composites (thermal-cold cycling temperature range: 20 ¡ãC ~ 490 ¡ãC).

GB/T 41739-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.99
CCS Y 80
Test method for dimensional stability of metal matrix
composites - Thermal-cold cycling method
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: FEBRUARY 01, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Test principle ... 4
4 Samples ... 4
5 Test devices and test procedure ... 5
6 Test results ... 7
7 Test report ... 8
Test method for dimensional stability of metal matrix
composites - Thermal-cold cycling method
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
4.1 Sample cutting and processing
Samples shall be cut mechanically at room temperature (15 °C ~ 25 °C).
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.
5.1.3 Heating and cooling device
The requirements for the heating and cooling device are as follows:
a) No matter which heating or cooling method is used, the temperature shall be controlled;
b) Either the heating device or the cooling device shall have a uniform temperature zone greater than the sample length, and the maximum temperature difference in the uniform temperature zone shall not be greater than 2 °C;
c) The heating and cooling rate of the sample shall be 5 °C/min.
5.1.4 Temperature measuring device
The temperature measurement accuracy of the thermocouple is ±0.2 °C.
5.1.5 Control system
The control system shall be able to set different temperature programs during the test and be able to perform automatic control. The control system shall be able to detect the shielding gas flow of the test system in real time. When the requirements of the test system cannot be met, the control system shall be able to automatically cut off the power. 5.1.6 Data collecting and processing system
The data collecting and processing system shall be able to continuously and automatically collect the data of the test temperature and length variation in the whole process, and be able to perform data analysis, calculation, drawing and correction. 5.2 Device calibration
The device has to be calibrated and then re-calibrated every six months. High-purity fused silica standard samples are used for device calibration. The test conditions and procedures used for device calibration, such as temperature history, ambient atmosphere, shall be the same as those used for testing samples. The obtained length variation shall be used as the baseline value, which is used to correct the experimental results during data analysis.