Uncertainty Evaluation in Measurement of Average Linear Expansion Coefficient of Beryllium Material

The average linear expansion coefficient of beryllium material was measured by thermal dilatometer. The factors of uncertainty affecting the measurement of average linear expansion coefficient of beryllium material were analyzed, and the measurement uncertainty of average linear expansion coefficient of beryllium material was evaluated. The results show that the main factors that affect the measurement uncertainty of average linear expansion coefficient the measurement repeatability, the measurement accuracy of thermal expansion analyzer, the measurement of initial length L₀ and the rounding off of values. In the range of (12.01-0.21)×10^-6 ℃^-1 to (12.01+0.21)×10^-6 ℃^-1 contains 95% of the possible value of average linear expansion coefficient, that is, the expanded uncertainty of average linear expansion coefficient is 0.21×10^-6 ℃^-1 under the 95% confidence level.