Heat treatment method that can effectively reduce the anisotropy of laser additive manufacturing titanium alloy

Abstract

The invention discloses a heat treatment method that can effectively reduce the anisotropy of titanium alloy manufactured by laser additive manufacturing. Due to the characteristics of rapid heating and rapid condensation in the laser additive manufacturing process, the titanium alloy obtained by laser additive manufacturing The structure of ‑6Al‑4V is composed of coarse primary β columnar grains that grow epitaxially through multiple cladding layers. In the grains, there are usually elongated martensite, widmansite, and basket structures, and the grain boundaries are continuously distributed with grains. The grain boundary α phase restricts the deformation path and easily induces cracks, resulting in prominent anisotropy and poor plasticity of the formed part. In view of the above problems, the high and low temperature cyclic heat treatment combined with the solution aging heat treatment method is adopted to make the original β columnar grain boundary discontinuous in laser additive manufacturing titanium alloy, the α phase of the continuous grain boundary is broken, and the primary α phase is spheroidized and precipitated into fine particles. The secondary α phase reduces the anisotropy and has excellent comprehensive properties.

Description

technical field [0001] The invention belongs to the field of laser additive manufacturing material forming processing; in particular, it relates to a heat treatment method capable of effectively reducing the anisotropy of laser additive manufacturing titanium alloys. Background technique [0002] Titanium alloy has the characteristics of high specific strength, good corrosion resistance and high heat resistance, and is often used to manufacture important load-bearing components such as beams, joints and bulkheads in large aircraft structures. In order to meet the higher requirements of light weight and reliability of aircraft structure, titanium alloy large-scale overall structure needs to be used more and more in large aircraft equipment. Due to the high resistance to cold deformation of titanium alloy, traditional processing and manufacturing methods are difficult to process large and complex structures. Parts, resulting in high cost of titanium alloy, long production cycl...

AI Technical Summary

Problems solved by technology

However, due to the characteristics of rapid heating and rapid condensation in the laser forming process, the Ti-6Al-4V structure obtained by laser additive manufacturing is composed of coarse primary β columnar crystals that grow epitaxially through multiple cladding layers. Slender martensite, widmansite, basket structure, and the grain boundary α phase is continuously distributed, the grain boundary α phase restricts the deformation path, and is easy to induce cracks, resulting in prominent anisotropy of the formed part, plasticity poor

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