Relation between phase transformations and mechanical properties of alloys in the Ti−Al−W−Zr system

Conclusions

• 1. The data of microstructural, differential, thermal, and x-ray phase analyses and the study of the “composition— properties” dependences have been used for plotting polythermic sections of the Ti−Al−W−Zr phase diagram at a variable content of aluminum and tungsten (0–20%).

• 2. With an increase in the content of one of the elements, i.e., aluminum or tungsten (at a fixed amount of the other elements), the strength characteristics of alloys in the Ti−Zr−Al−W system at room and high (600–800°C) temperatures increase. The behavior of these curves changes when the aluminum content exceeds 9%; they become horizontal at 600 and 700°C and drop markedly at 800°C and at room temperature.

• 3. The plasticity characteristics of the alloys largely depend on their phase composition. At room temperature the values of δ and ψ of the alloy bearing 6% Al and 6% W drop jumpwise. The specific elongation decreases substantially at 600–800°C in the case of alloying with tungsten and aluminum, and the specific reduction of area decreases substantially in alloys with an aluminum additive. At 7–10% W, the value of ψ is maximum (ψ≅100%) at 700–800°C and attains almost 70% at 600°C.