Formation and thermal stability of liquid phase in layered film systems

• Phase transitions in layered Cu/Bi/Cu and Cu/Pb/Cu films have been studied.
• Size and shape of Bi inclusions affect the value of its supercooling.
• Supercooling of Bi and Pb in a copper matrix is 120 K and 80 K respectively.

The results of studying the melting–crystallization phase transitions in multilayer films, which are the model for the systems “the particle embedded in the refractory matrix”, are presented. The value of supercooling during the fusible component crystallization in multilayer Cu–Bi–Cu and Cu–Pb–Cu films, of 120 and 80 K respectively is determined by using in situ techniques of electrical resistance and electron diffraction measurements. It has been determined that the size and shape of Bi inclusions affect the nature of the crystallization and the value of supercooling. Maximum supercooling takes place in case Bi in the sample is present in the form of isolated nanoparticles. It has been found that the thermal stability of the copper film depends on the substrate material on which the samples are formed and it is sharply reduced in the presence of even small amounts of lead.