A Method for Endless Diffusion Connection of Ring Structural Parts

Abstract

In an annular structural member infinite place diffused connecting method, the inner annular face of a TiAl rim and the annular face of a Ti2AlNb wheel boss are designed into inclined interfaces; in diffused connecting, when the expansion distance difference is generated, the TiAl rim automatically drops along the inclined interfaces, and it is ensured that a TiAl / Ti2AlNb alloy connecting face isin a contact state all the time. When the TiAl rim reaches the temperature, the Ti2AlNb wheel boss still continues to expand when not reaching the diffused connecting temperature, then the Ti2AlNb wheel boss can extrude the TiAl rim, the diffused connecting pressure is generated on the diffusing and connecting face, and the diffused connection of the TiAl alloy rim and the Ti2AlNb alloy boss is realized. By designing a proper annular connector structure, the proper, simple and controllable diffused connecting pressure is generated on the diffused connecting face only according to the structural characteristics without exerting external radial pressure, exerting constraints or adding a clamp. Only the lower pressure of 2MPa is exerted in the whole diffused connecting process, the smooth falling process is ensured, the process is simple in the whole diffused connecting process, the requirements for devices are greatly lowered, and the cost is reduced.

Description

technical field [0001] The invention relates to the field of solid-state welding, in particular to a method for diffusion connection of annular structural parts of dissimilar intermetallic compounds with large expansion coefficients of outer metals. Background technique [0002] Ti-Al intermetallic compounds have the characteristics of low density, high specific strength and good oxidation resistance. They are ideal lightweight high-temperature metal structural materials and have broad application prospects in the fields of aero-engines and aerospace vehicles. Among them, the service temperature of TiAl alloy can reach 700-900 ° C, Ti 2 The use temperature of AlNb alloy can reach 650℃. However, Ti-Al alloys are inherently brittle and difficult to process, which limits their applications. Diffusion bonding is an important method to realize the forming of complex intermetallic compounds, so the research and development of TiAl / Ti 2 AlNb alloy diffusion bonding method is cru...

AI Technical Summary

Problems solved by technology

Although this method can realize the diffusion connection of ring parts with a larger expansion coefficient of the outer layer metal and reduce the probability of TiAl cracking, it is difficult to manufacture the fixture, and the requirements for the fixture are relatively high. The fixture is easily damaged during use, which increases the cost.

At the same time, the overall stress of the TiAl rim is relatively large, and there is a risk of cracking

[0007] Currently, for TiAl alloys and Ti 2 The research on diffusion bonding of AlNb alloy rings is not deep enough, and there are few related reports

Moreover, the expansion coefficient of the outer metal TiAl alloy is large, and it is difficult to obtain the expansion pressure difference by conventional methods; if it is necessary to impose rigid constraints on the boundary for thermal self-pressure diffusion connection or use special fixtures, it is easy to generate large residual stress

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