The analogy between martensitic transformation and laser threshoId behaviour is ernphasised.The emission ratio of coherent phonon is given and the phonomenon of premartensitic soft mode is explained.

• 本文强调了马氏体相变与激光阈行为的类似;推导出了相干声子的发射率公式,并解释了先于马氏体相变的软模现象。