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摘要: 本文采用0.1 s脉冲CO2激光快速加热厚度为微米量级的铝箔、康铜箔、氮化硼片样品,并使用参考激光束造成单缝衍射。然后,通过光电转换装置,实现长度、光强、电压的转化过程,来观测物体被快速加热时,热膨胀量随时间的变化情况。首次直接观测到了热膨胀的动态过程并摄下了膨胀的弛豫曲线。在此基础上就铝样品考察了弛豫时间与样品长度的关系。最后,对热膨胀动态过程的机制进行了讨论。Abstract: In this work, CO2 laser pulse of 0.1 s was used to heat instantly the thin specimens of Al, constantan, BN with the thickness of 20~100 m, and a system of the slit diffraction using He-Ne laser was also adopted. By a photoelectric converting device, the change of the specimen length was transferred to the change of light strength, then to that of voltage. Using above method, we have observed and measured the changing process of the thermal expansion amount of the specimen with time during the specimen was heated instantly. For the first time, the dynamic-process of thermal expansion was observed directly and the oscillograms of the relaxation curves of thermal expansion were obtained. On the basis of above experiment, we have examed the relation between the relaxation time and the specimen length for Al. The mechanism of the dynamic-process of thermal expansion has also been discussed.
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Key words:
- dynamic-process of thermal expansion /
- direct observation /
- mechanism
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Zhou Benlian. Thermophysical Properties. Proc 1st ATPC. China Academic Publishers, 1986: 39. 周本濂. 热膨胀动态过程的理论和实验研究. 高压物理学报, 1988, 2(2): 119. Xu Chengfa, Zhou Benlian, Ye Qinghe. Thermophysical Properties. Proc 1st ATPC. China Academic Publishers, 1986: 587. Carslaw H S, Jaeger J C. Conduction of Heat in Solid. New York: Oxford Univ Press, 1958: 101. 卡姆克 E. 常微分方程手册. 北京: 科学出版社, 1977: 514.
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