Abstrakt
Aim of this work is to study phase transformations in metastable beta zirconium alloys based on well known transformations in metastable beta titanium alloys. Titanium alloys are commonly used for example in aircraft industry or in biomedicine.
Metastable beta titanium alloys are the most studied group of Ti alloys nowadays. They have got unique properties such as high strength and low modulus of elasticity.
Especially strength can be further improved by thermomechanical treatment. Zirconium is in the same group of periodic table of elements as titanium and exhibits similar behavior in terms of phase transformations.
Zirconium and its alloys are used especially in nuclear reactors due to its low cross-section for thermal neutron caption. In this work, phase transformations in Ti-(12-18)Mo as well as in Zr-(12-18)Nb alloys were studied in situ by electrical resistivity measurements.
Based on these results, the alloys were linearly heated with the same rate to temperatures in the range of 300 - 500°C and subsequently quenched in order to study phase composition, microstructure and mechanical properties ex-situ. Achieved results for the studied Ti and Zr alloys were compared and discussed.
In the Zr-Nb alloys, beta phase (bcc) is in metastable state and, similarly to Ti-Mo alloys, omega phase and alpha phase form upon heating.