Vacuum diffusion bonding method for TC18 titanium alloys

Abstract

The invention discloses a vacuum diffusion bonding method for TC18 titanium alloys. When diffusion bonding is performed, diffusion bonding parameters are controlled and implemented reasonably, and organizational evolvement control is performed on obtained bonded TC18 titanium alloy solid solution samples, so that TC18 titanium alloy diffusion bonding and heating treatment technologies are coupled mutually, the interface bonding quality is high, meanwhile, solid solution treatment of titanium alloy base metals is performed, and the content of primary alpha phases in microscopic structures is adjusted. Secondary alpha phases are separated out of alloy metastable beta phases by controlling furnace cooling temperatures, meanwhile, elements adjacent to titanium alloy bonded sample interfaces are diffused further, and the microscopic structures are completely evolved to form metallurgical bonding, so that the excellent comprehensive mechanical performance matching and the high bonding strength are obtained. Tests indicate that the tensile strength of diffusion bonding joints of the TC18 titanium alloys is not lower than 1000MPa, the impact toughness of the joints is not lower than 30J/cm2, the cross section contraction percentage of the joints is not lower than 15%, and the comprehensive mechanical performance matching is good.

Description

Technical field [0001] The invention relates to the field of titanium alloy solid-state welding, in particular to a TC18 titanium alloy diffusion bonding method for controlling microstructure. Background technique [0002] Titanium alloy has many advantages such as high specific strength and good mid-temperature performance. It is one of the important materials for the preparation of advanced and complex structural parts required by the aerospace industry. Diffusion bonding technology is an important forming method for complex integral structural parts. The manufacturing requirements also have the advantages of improving the utilization rate of materials, so domestic and foreign scholars have conducted research on titanium alloy diffusion bonding technology. [0003] The Beijing Institute of Aeronautical Materials has proposed a low-temperature vacuum diffusion bonding method of titanium alloy in the patent publication number CN101392363A. This method uses magnetron sputtering to s...

AI Technical Summary

Problems solved by technology

This alloy belongs to the nearly β-type titanium alloy. Compared with other titanium alloys, its phase transition temperature is lower and the thermal stability of the microstructure is weak. Coarsening leads to deterioration of material properties, but too low diffusion bonding temperature leads to a decrease in the connection quality of the joint. Therefore, it is difficult to select a near-β titanium alloy diffusion bonding temperature that can obtain high bonding quality, which limits the development of TC18 titanium alloy diffusion bonding technology.

In addition, in the manufacture of integral components, the heat treatment and connection of materials are two processes, and there is a certain degree of contradiction in the realization process: the use of heat-treated materials for connection will cause the material structure to deteriorate during the connection process, thereby affecting the performance of components; and Heat treatment is performed on the overall components after connection to adjust the structure and properties of the component materials, which is technically difficult and easily causes component deformation, consuming manpower and energy

The above shortcomings limit the application of diffusion bonding in the manufacture of important structural parts of titanium alloys

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