纤维复合材料的热膨胀系数

提出了一种利用压电光声技术测量材料热膨胀系数的实验方法,并测试了单向复合材料C/C、C/Al的横向、纵向的热膨胀系数。根据已有的理论计算方法与实验结果对该方法的测试结果进行验证,证明了该检测方法的可靠性,进而又测量了C/C、C/Al材料在任一方向上的热膨胀系数。这种方法克服了理论计算过程复杂以及常规手段无法测量任一方向上热膨胀系数的缺陷。

THERMAL EXPANSION COEFFICIENT OF FIBER COMPOSITES

The thermal expansion coefficients of fiber composites are studied in this paper. A method of measuring the thermal expansion coefficient by piezoelectric photoacoustic technique was proposed. An intensity-modulated Ar+ laser beam was used as the incident light. The beam was focused on an about 1μm diameter spot and illuminated collinearly the sample surface. Using the technique, piezoelectric photoacoustic signals as a function of different frequencies were experimentally measured. The thermal expansion coefficients can be obtained by fitting the experimental data. On the other hand, the thermal expansion coefficients of one-way composite C/C and C/Al in the transverse, longitudinal directions were measured. The measured results are reliable by comparing with other calculation methods and experimental results. Thermal expansion coefficients in arbitrary directions of C/C and C/A were given. The defects of the theoretical calculation method, which is complicated and by which the thermal expansion coefficient in arbitrary directions can not be measured, are overcome.