Heat treatment method for regulating and controlling static and dynamic load mechanical properties and anisotropy of SLM titanium alloy

Abstract

The invention discloses a heat treatment method for regulating and controlling static and dynamic load mechanical properties and anisotropy of an SLM titanium alloy. The SLM forming manner enables a microstructure of a formed part to have an obvious thick columnar crystal structure, so that the mechanical properties of the formed part have obvious anisotropy. The SLM Ti-6Al-4V formed part is subjected to heat treatment including circulating spheroidizing annealing and solid solution aging, and a double-state structure is obtained. After heat treatment, the plasticity of a sample piece is greatly improved (the elongation reaches 18.35%), the mechanical properties exceed the forging standard, the sample stability is improved, and the anisotropy of plasticity is greatly reduced; after circulating spheroidizing annealing and solid solution aging heat treatment, the fracture toughness of the sample piece is 85.5 MPa, and the anisotropy is smaller than or equal to 15%; when the strain amplitude is larger than or equal to 0.9%, the low-cycle fatigue performance of the sample piece subjected to heat treatment is higher than that of a forged piece; the crack propagation path in the double-state structure is longer than that of the forged piece; when the strain amplitude is 0.7%-0.9%, the low-cycle fatigue performance is equivalent to that of the forged piece; and when the strain amplitude is smaller than or equal to 0.7%, the low-cycle fatigue performance is smaller than that of the forged piece.

Description

technical field [0001] The invention belongs to the technical field of metal laser additive manufacturing, and the manufactured titanium alloy structural parts can be applied in the fields of aerospace, chemical equipment, medical construction, and shipbuilding industry, especially in industries that have certain requirements for static and dynamic load-bearing properties and anisotropy In the field of manufacturing, the heat treatment system of selective laser melting (SLM) titanium alloy has been improved and supplemented, and a new method for the processing and manufacturing of aerospace titanium alloy structural parts has been provided. Background technique [0002] SLM additive manufacturing technology is developed on the basis of selective laser sintering technology, and it is one of the most popular near net shape methods in recent years. SLM technology slices the model through the slicing software that comes with the system, and then uses a high-energy laser beam to ...

AI Technical Summary

Problems solved by technology

During the SLM forming process, the sample is heated and cooled quickly, which will produce coarse β columnar crystals, which makes the matching degree of plasticity and toughness poor. The titanium alloy produced by SLM has high strength, but its plasticity and toughness are relatively low, and the same forming process The anisotropy of the mechanical properties of the formed parts is quite different

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