The influence of melting processes and parameters on the structure and homogeneity of titanium-tantalum alloys
- Los Alamos National Lab., NM (United States). Materials Science and Technology Div.
- Sandia National Lab., Albuquerque, NM (United States). Materials and Processes Science Center
Alloys of titanium with refractory metals are attractive materials for applications requiring high temperature strength and corrosion resistance. However, the widely different characteristics of the component elements have made it difficult to produce sound, compositionally homogeneous ingots using traditional melting techniques. This is particularly critical because the compositional ranges spanned by the micro- and macrosegregation in theses systems can easily encompass a number of microconstituents which are detrimental to mechanical properties. This paper presents the results of a study of plasma (PAM) and vacuum-arc (VAR) melting of a 60 wt% tantalum, 40 wt% titanium binary alloy. The structural and compositional homogeneity of PAM consolidated +PAM remelted, and PAM consolidated +VAR remelted ingots were characterized and compared using optical and electron microscopy and x-ray fluorescence microanalysis. Additionally, the effect of melting parameter, including melt rate and magnetic stirring, was studied. The results indicated the PAM remelting achieves more complete dissolution of the starting electrode, due to greater local superheat, than does VAR remelting. PAM remelting also produces a finer as solidified grain structure, due to the smaller molten pool and lower local solidification times. Conversely, VAR remelting produces an ingot with a more uniform macrostructure, due to the more stable movement of the solidification interface and more uniform material feed rate. Based on these results, a three-step process of PAM consolidation, followed by a PAM intermediate melt and a VAR final melt, has been selected for further development of the alloy and processing sequence.
- DOE Contract Number:
- W-7405-ENG-36; AC04-94AL85000
- OSTI ID:
- 237696
- Report Number(s):
- CONF-9510290-; ISBN 1-878954-58-X; TRN: 96:013482
- Resource Relation:
- Conference: International conference on tungsten and refractory metals, their alloys, composites and carbides, McLean, VA (United States), 15-17 Oct 1995; Other Information: PBD: 1996; Related Information: Is Part Of Tungsten and refractory metals 3, proceedings; Bose, A. [ed.] [Parmatech Corp., Petaluma, CA (United States)]; Dowding, R.J. [ed.] [Army Research Lab., Watertown, MA (United States)]; PB: 265 p.
- Country of Publication:
- United States
- Language:
- English
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