Phase constitution in the solution-treated and quenched state and the heat treatment
behavior were investigated by electrical resistivity, hardness, and elastic modulus measurements,
X-ray diffraction, and optical microscopy. Hexagonal martensite and the β phase were
identified in the Zr-5mass%Nb alloy. β and ω phases were identified in the Zr-10 and
15mass%Nb alloys, and only the β phase was identified in the Ti-20Nb alloy. Resistivity at RT,
Vickers hardness and elastic modulus increased up to 10Nb and then decreased dramatically at
15Nb. Above 15Nb, these values slightly decreased. The elastic moduli for 15Nb and 20Nb
were 59.5 and 55.5 GPa, respectively. On isochronal heat treatment, the isothermal ω phase
precipitated between 473 and 623 K and then the α phase precipitated in the 10Nb, 15Nb and
20Nb alloys.