O. P. Shaboldo, Ya. M. Vitorsky, V. V. Sagaradze, E. G. Volkova, N. L. Pechorkina
EFFECT OF THERMOMECHANICAL TREATMENT ON THE FORMATION OF THE STRUCTURE OF HIGH-STRENGTH Nb- AND Ti-BASED ALLOYS
The paper studies the effect of heat treatment conditions on the microstructure of the LN-1 (Nb–10W–5Mo–1.5Zr–0.15C) and TS6 (Ti–10.5Cr–7V–4Mo–3Al–1Zr) alloys. It is shown for the LN-1 alloy that, under specific temperature conditions, a sufficiently high level of plasticity, necessary for subsequent deformation, is realized in the alloy. The structural studies have revealed the formation of finely dispersed niobium-zirconium carbides in the matrix during thermomechanical strengthening with the use of preliminary annealing. It is demonstrated that cold deformation by drawing (ε=24%) of the TS6 alloy leads to the formation of a cellular-band structure with high dislocation density along the cell boundaries. In the process of subsequent aging, the β-phase disintegrates with heterogeneous isolation of thin α-phase plates thus ensuring a considerable increase in the strength characteristics of the alloy.
Keywords: high-temperature niobium alloys, carbides, β-titanium alloy, cold deformation, aging, α-phase, electron microscopy, mechanical properties, strengthening