Role of martensite transformation in variation of physicomechanical properties of niobium-titanium (45 and 50 wt.% niobium) alloys at low temperatures.

It is shown that the direct and reversible transformation, which proceeds orientationally, leads to: 1) anomalous temperature dependences of the relative elongation, proportionality limits and yield strength of hardened and drawn samples at 160-77 K, the degree of anomaly being dependent on the thermomechanical treatment; 2) pseudo-elasticity in the stress-strain curves, the temperature range of the pseudo-elasticity being dependent on the thermomechanical treatment; and 3) non-monotonous behaviour in the strain dependences of electrical resistance and stress in all structural states.