Method for obtaining tri-modal microstructure in dual-phase titanium alloy through furnace cooling

Abstract

The invention discloses a method for obtaining a tri-modal microstructure in dual-phase titanium alloy through furnace cooling. The method comprises the following steps of: carrying out heat insulation water cooling at near beta temperature; carrying out heat insulation furnace cooling in a common two-phase region and carrying out heat insulation air cooling in a two-phase region at lower temperature. 10-20% of primary equiaxial alpha phases are remained in a titanium alloy microstructure through carrying out heat insulation water cooling at near beta temperature, and the rests are martensites. A test sample microstructure is changed into alpha equal axle, alpha thick silvers and beta residues through carrying out heat insulation furnace cooling in the common two-phase region. The titanium alloy with the tri-modal microstructure is obtained through carrying out heat insulation air cooling in the two-phase region at lower temperature. The method is free of near beta thermal deformation, deformation and nonuniform thermal effect and easy for temperature control, and a dual-modal microstructure can be obtained without carrying out special pretreatment on a primary equiaxial microstructure of the titanium alloy. The method is simple, convenient, feasible and wide in application rang and can be widely used for thermal treatment of titanium alloy parts manufactured by using methods such as rolling, squeezing, machining, forming and the like so as to obtain the tri-modal microstructure.

Description

technical field [0001] The invention relates to the technical field of thermal processing of titanium alloys, in particular to a heat treatment method for obtaining a triple-state structure through furnace cooling in a dual-phase titanium alloy with an equiaxed structure or a double-state structure. Background technique [0002] As a high-performance material, duplex titanium alloy has the advantages of low density, high specific strength, high temperature resistance, and corrosion resistance. It plays an important role in aerospace, petrochemical, and biopharmaceutical fields. Especially as a key load-bearing structural part in aviation, it requires not only good room temperature strength plasticity, fracture toughness, fatigue performance, crack growth resistance and high temperature performance. The microstructure of titanium alloy determines its service performance. Duplex titanium alloy has equiaxed structure, two-state structure, Widmanstatten structure, basket struct...

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Problems solved by technology

[0004] In order to overcome the problems in the prior art that the temperature range is narrow, it is not convenient to control the forging temperature, and the limitation of the initial structure is a two-state structure, and the thickness of the secondary lamellar α in the obtained three-state structure is too small problem, the present invention proposes a method for obtaining a triple-state structure in a dual-phase titanium alloy by furnace cooling

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