THE INVESTIGATION OF CLUSTERS DECAY IN COMPLICATED METAL MELTS: Ni-Cr-Mo-W-Nb-C I. I. Panchenko, N. M. Kochegura, Institute of Foundry Problems, Ukrainian National Academy of Sciences, Kiev, Ukraine.

One of informed characteristics of the melt's structure is it's density. The density is responded on the change of melt structure which is connected with the clusters quantity and their size. In the study of complicated metal melts (Ni-Cr-Mo-W-Nb-C) cluster decay and the changes in the melt density was observed. This procedure was done to show a non-reversible clusters decay of these elements after the thermal effect. this phenomenon was discovered by the means of gamma-absorbing technique of the density measurement. The measurement was performed continuously in the temperature interval of 293-2093 K. There was the temperature hysteresis of melt density after such thermal treatment. The density of cooling melts was lower then one of the heating melts if compare at the same temperature point. This hysteresis of the density took place due to the Mo-, W-, Nb- and Cr-clusters decay and their turning to the solution. This phenomenon was a threshold process. It was necessary to transfer the melt up to higher energy level to the refractory element clusters be decayed. This crossing transition achieved after the fixed temperature - homogenising temperature. It is concluded that gamma-absorbing technique of the density measurement is a possible mean of study non-reversible cluster decays after different melt treatments. In addition, laser or electron beam treatment of melts changed the energy state of melt too and could be studied using this method.