Niobium zirconium alloy not only maintains the low temperature plasticity of niobium, but also has higher mechanical properties than pure niobium. The addition of zirconium to niobium can improve the strength of the alloy without affecting the plasticity and processing property of the alloy, improve the high temperature strength and high temperature oxidation resistance of niobium, zirconium can also improve the oxidation resistance and alkali metal corrosion resistance of the alloy. NbZr10 is a new kind of functional niobium alloy material, through the electric arc furnace smelting, active metal elements Zr solid solution strengthening, at the same time to join the ageing strengthening of the elements of C through proper processing and heat treatment to control the distribution of the precipitation of the carbide form, in order to improve the strength of NbZr10 alloy material, and can greatly improve the alloy high temperature creep resistance. In this paper, the arc furnace smelting method is chosen to carry out two smelting to avoid the problems of vacuum electron beam smelting, such as the serious melting loss of zirconium atoms, high melting temperature, high superheat, zirconium alloy elements in niobium matrix metal niobium distribution is not uniform phenomenon. By controlling the impurity composition of niobium plate and zirconium plate, the content of gap element in alloy ingot can be controlled to ensure reasonable alloy composition.
The overall composition of NbZr10 alloy ingot is uniform, and only micro segregation occurs in the alloy. The as-cast microstructure is fine and long dendritic rod-like structure and short and thick dendritic rod-like structure. There is obvious segregation phenomenon on the grain boundary of large dendrite, which contains more undissolved Zr-rich phase, and fine equiaxed dendrite structure is distributed between large dendrite. After homogenized annealing treatment at 1300℃ for 24h, the undissolved Zr-rich phases in the dendrite and grain were dissolved, segregation was significantly reduced, and the grain boundary in the microstructure became clear. NbZr10 alloy to make use of hot rolling test of high temperature processing performance, temperature 1323 k, the deformation of 10%, 15% and 20%, roll Φ 550 mm diameter, roll speed 30 mm/min. The deformation of alloy billet is uniform, and there is no obvious crack edge phenomenon. The alloy structure is obvious streamline in hot working, and recovery recrystallization occurs. According to the parameters of hot rolling test, the temperature of thermal simulation test is 1273K, 1123K and 1373K, and the strain rates are 0.01s-1, 0.1s-1 and 1 s-1. The Gleeble-1500 thermal simulation machine was used to carry out isothermal constant strain rate compression test and the high temperature deformation behavior was studied. Thus, it provides a reference for reasonably controlling the hot forming process of NbZr10 alloy, improving its comprehensive mechanical properties, formulating reasonable hot working technology, and providing a theoretical basis for industrial production and rolling. The true stress-strain curves of hot compression of NbZr10 alloy were obtained according to the thermal simulation experiments. Finally, the mechanical properties and stress-strain constitutive equations of NbZr10 alloy under high temperature deformation were established.
