Study On Rolling Technology, Deformation Microstructure And Properties Of TZM Alloy Plate

The TZM alloy (Titanium-Zirconium-Molybdenum Alloy) is present widely applicated as a kind of high-temperature alloy in Molybdenum alloys. And it possessed high melting-point, large strength, high elasticity modulus, little expansion coefficient, low vapor pressure, good electric conductivity and thermal conductivity, strong corrosion resistance as well as good high temperature mechanical properties.In this thesis, the TZM alloy plate was prepared by power metallurgy technology, and the fine-grained TZM alloy plate was deformed by a large compression ratio hot-rolling, finally the TZM alloy plate was annealing after hot-rolling. In the preparation process, the influences of Zirconium and Titanium elements on TZM alloy sintering were studied. Based on fine-grained TZM alloy plate, the densification was explored by hot-rolling. The capacity of hot-rolling densification, the mechanism of hot-rolling densification and laws of densification and the mechanism and laws of strengthening of fine-grained TZM alloy plate were studied. Microstructure, property and changes and the effect on microstructure and property by hot-rolling and follow-up of heat treatment were researched. The main results are as follows:(1) The element of Ti and Zr were added to TZM alloy as form of TiH2 and ZrH2, which reduced the density of sintered molybdenum slightly, but the grains of sintered molybdenum were refined. The results indicated that the alloyed element Zr and Ti, on the one hand were solved into the Mo matrix, on the other formed (Mo, Ti, Zr)xOy composite oxide particles with Mo and oxygen in the alloy, and existed in grains between internal and surface. This kind of dispersion phase absorbed the oxygen and fixed the dislocation in the TZM alloy, thus improved the strength of TZM alloy.(2) The TZM alloy plate compared with pure molybdenum plate of rolling technology, we should improve the temperature of breakdown rolling, finish thermo-rolling and tempreture rolling, and add annealing tempreture in heat treatment process. (3) The results showed that the deformation temperature and pressure were two of the main influential factors of processing conditions for TZM alloy plate by hot-rolling deformation, and the parameters of annealing technology also significantly affect the microstructure and property after the rolling. To choose the right deformation temperature, the compression ratio, the total compression ratio, design and reasonable parameters of annealing technology were the key issues.(4) The TZM alloy plate was deformed and densified by a large compression ratio rolling to increase the strength and elongation. The properties were regulated by heat treatment finally, so that grain was lengthened and fibrosised by rolling. Internal boundary impurities segregation decreased significantly. The effect on performance by the compression ratio of hot-rolling was studied. It showed that strength and elongation significantly increased with the increase of deformation after the hot-rolling.