Method for controlling structure refinement of cast TiAl-based alloy and form of boride

A technology of borides and base alloys, which is applied in the field of intermetallic compound alloy preparation, can solve the problems that the shape, size and distribution of borides cannot be improved, and achieve the effect of fine grain size, uniform size distribution and uniform structure distribution

Inactive Publication Date: 2011-04-13
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Thermomechanical deformation methods such as isothermal forging or hot extrusion can achieve the purpose of improving the shape, size and grain refinement of borides, but for casting γ-Ti...

Method used

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  • Method for controlling structure refinement of cast TiAl-based alloy and form of boride
  • Method for controlling structure refinement of cast TiAl-based alloy and form of boride
  • Method for controlling structure refinement of cast TiAl-based alloy and form of boride

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Experimental program
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Effect test

Embodiment 1

[0035] The nominal composition of the alloy used in the experiment is Al: 47, Cr: 2, Nb: 2, B: 0.8, the balance is Ti (atomic percentage at.%), and the zero-grade sponge titanium with a purity of 99.76% and a purity of 99.99% are selected. High-purity aluminum ingots, pure chromium particles with a purity of 99.90%, niobium flakes with a purity of 99.9% and Ti-3B master alloy are used as raw materials. Put the raw materials into the non-consumable vacuum electric arc furnace and evacuate to 6×10 -3 Pa, filled with high-purity argon to 0.5×10 5 Pa, repeated smelting 4 times, the smelting current is 400-1200A, and a master alloy ingot with a weight of 1.2Kg is prepared. The alloy sample of Φ14mm×80mm is cut by wire cutting method, and filled with Al 2 o 3 -Y 2 o 3 The double-layer structure ceramic tube is placed in a vacuum heat treatment furnace for 30 minutes, and the holding temperature is 20°C below the liquidus temperature, and then quickly quenched into the gallium-i...

Embodiment 2

[0042] The nominal composition of the alloy used in the experiment is Al: 47, Cr: 2, Nb: 2, B: 0.8, the balance is Ti (atomic percentage at.%), and the zero-grade sponge titanium with a purity of 99.76% and a purity of 99.99% are selected. High-purity aluminum ingots, pure chromium particles with a purity of 99.90%, niobium flakes with a purity of 99.9% and Ti-3B master alloy are used as raw materials. Put the raw materials into the non-consumable vacuum electric arc furnace and evacuate to 6×10 -3 Pa, filled with high-purity argon to 0.5×10 5 Pa, repeated smelting 4 times, the smelting current is 400-1200A, and a master alloy ingot with a weight of 1.2Kg is prepared. The alloy sample of Φ14mm×80mm is cut by wire cutting method, and filled with Al 2 o 3 -Y 2 o 3 The double-layer structure ceramic tube is placed in a vacuum heat treatment furnace for 30 minutes, and the holding temperature is 20°C below the liquidus temperature, and then quickly quenched into the gallium-ind...

Embodiment 3

[0046] The nominal composition of the alloy used in the experiment is Al: 47, Cr: 2, Nb: 2, B: 0.8, the balance is Ti (atomic percentage at.%), and the zero-grade sponge titanium with a purity of 99.76% and a purity of 99.99% are selected. High-purity aluminum ingots, pure chromium particles with a purity of 99.90%, niobium flakes with a purity of 99.9% and Ti-3B master alloy are used as raw materials. Put the raw materials into the non-consumable vacuum electric arc furnace and evacuate to 6×10 -3 Pa, filled with high-purity argon to 0.5×10 5 Pa, repeated smelting 4 times, the smelting current is 400-1200A, and a master alloy ingot with a weight of 1.2Kg is prepared. The alloy sample of Φ14mm×80mm is cut by wire cutting method, and filled with Al 2 o 3 -Y 2 o 3 The double-layer structure ceramic tube is placed in a vacuum heat treatment furnace for 30 minutes, and the holding temperature is 20°C below the liquidus temperature, and then quickly quenched into the gallium-i...

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Abstract

The invention discloses a method for controlling the structure refinement of a cast TiAl-based alloy and the form of boride. The method can effectively control the form and size of boride while uniformly refining the TiAl-based alloy cast structure. The method comprises the following steps: performing the semisolid isothermic thermal insulation treatment, wherein the temperature is 5-20 DEG C lower than the temperature of the alloy liquidus; and performing the solid aging thermal treatment to further refine the alloy structure and obtain the near lamellar structure with tiny lamella groups. The process provided by the invention needs no hot mechanical treatment of canned-forging in multiple steps, thereby greatly increasing the available size of the alloy material and reducing the processing cost of the unused casting alloy.

Description

technical field [0001] The invention belongs to the technical field of preparation of intermetallic compound alloys, and in particular provides a process method for how to obtain a fine and uniform nearly full lamellar structure of as-cast boron-containing TiAl-based alloy and control the form, size and uniform distribution of borides. Background technique [0002] The density of γ-TiAl alloy is less than 4g / cm 3 , with high specific strength and specific modulus of elasticity, it can still maintain high enough strength and stiffness at high temperatures, and it also has good creep resistance and oxidation resistance, which makes it ideal for aerospace, aviation and automotive engines Very competitive material for heat-resistant structural parts. [0003] However, the strong columnar grain growth tendency and coarse lamellar structure characteristics of cast γ-TiAl alloys lead to poor room temperature plasticity and anisotropy of properties, so the grain or lamellar refinem...

Claims

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Application Information

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IPC IPC(8): C22F1/18C22C14/00
Inventor 郑立静王建吉杨莉莉张虎
Owner BEIHANG UNIV
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