Synytsina Y. AMg6 alloy structure formation in welding joints of critical products for long operating time.

The present Candidate dissertation is directed for the prolongation of operating time of welding joints for critical products made from AMg6 alloy. Presence and temperature conditions of definite morphology cluster compounds formation in industrial AMg6 melt have been determined for the first time. The investigation of AMg6 alloy structure formation during its' melting and solidification under the specific for welding intervals of cooling rates has been developed. The determination of association between excess phases based on Al and Mg abstraction along grain boundaries depending from cluster structure in AMg6 melt has been developed. The obtained data allows the proper welding modes development for long - term storage critical products. The investigation of cluster compounds structure quantity characteristics in AMg6 alloy melt (in the area of above-liquidus temperatures) has been developed. This fact allows the knowledge development both about the processes which take place in AMg6 alloy melt and their influence on structure formation under the solidification of alloys based on Al. Also, it makes possible to investigate the processes of natural aging in AMg6 alloy welding joints during their long-term storage. The investigation of grain-boundary cracking in AMg6 alloy welding joints after overheating has been developed