Thermoelectric processes at rapid cooling of solidifying metals

J. Klavins - A. Mikelsons - A. Poznyaks - J. Valdmanis

Institute of Physics, Latvian University, Salaspils-1, LV-2169, Latvia

Abstract
The aim of the paper is to discuss thermoelectric phenomena specific in molten and solidifying metals at intense local surface cooling. Results of various experiments with Ga, Bi, Cd, Zn, Sn as well as numerical simulation of metal solidification process are presented. In the experiments many times was fixed generation of sharp magnetic field impulses (pikes). It is magnetic field of thermocurrents what arises because of inhomogeneity of solidifying or just solidified metal. The results analysis allows to advance two possible reasons of investigated thermoelectric effects. The first is metal liquid phase overcooling near the solidification front, moreover overcooling degree is different along the front. The second possible reason - inhomogeneities of metal mechanical state, its rapid changes and mechanical stresses directed tangentially to the solidification front. Figs 10, Refs 8.