Research on the Process of Al–Mo–Ti Master Alloy Dissolution in Titanium


This paper presents the results of studying the behavior of the components of the molybdenum-containing Al-(48-52)Mo-(6-9)Ti (wt. %) master alloy when it is dissolved in liquid titanium. The nature and characteristics of the dissolution of the master alloy in titanium were judged by the results of X-ray microanalysis of the matrix phases (titanium, master alloy) and transition zones (phase boundary). In order to bring the model closer to actual melting conditions, a vacuum arc melting of a titanium sample was used, in which a certain amount of master alloy was encapsulated. The samples were melted around the perimeter so that the liquid titanium only began to interact with the master alloy, after which the melting process was stopped. The obtained results suggest that the composition of the Al-Mo-Ti master alloy is changed by the diffusion transition of molybdenum and aluminum into the titanium melt and counter diffusion of titanium into the master alloy melt. At the same time, a decrease in the concentration of molybdenum in the master alloy is compensated by aluminum and titanium. For every 1.0 wt. % of Al converted into Ti about 2.0 wt. % of Ti dissolves in the master alloy melt. The revealed patterns of changes in the composition of the Al-Mo-Ti master alloy when interacting with liquid titanium suggest that under vacuum-arc melting of titanium alloys the dissolution of the master alloy should not lead to the formation of refractory phases.

Keywords: titanium, molybdenum, aluminum, master alloys, dissolution

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