Thermo-Hydrogen Refinement of Titanium Microstructure After Near-Net Shape
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Solution Overview
Problem
Traditional processes for producing high-performance titanium materials are energy-intensive and limit the production of complex geometries, compromising mechanical performance, while near-net-shape technologies like casting and additive manufacturing fail to achieve optimal microstructures.
Innovation Solution
A thermo-hydrogen refinement process that involves heating titanium materials under a hydrogen-containing atmosphere above the β transus temperature, followed by cooling and dehydrogenation, to create a refined microstructure of α and β phases, eliminating the need for deformation and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional wrought processing is used to produce high-performance titanium materials, then mechanical performance is improved, but energy consumption increases significantly
Solution Approach 1:
The patent applies parameter changes by utilizing hydrogen atmosphere and temperature control (above and below beta transus temperature) to transform the microstructure of titanium materials. This thermal-hydrogen treatment process refines the grain structure and phase composition without requiring traditional thermomechanical processing, thereby achieving high mechanical performance with reduced energy consumption.
Solution Approach 2:
The patent exploits phase transitions of titanium, specifically the alpha-beta phase transformation that occurs at the beta transus temperature. By heating above this temperature and then controlling cooling, the material undergoes phase changes that refine the microstructure and enhance mechanical properties without the need for deformation processes.
2Strength
If traditional wrought processing is used to produce high-performance titanium materials, then mechanical performance is improved, but manufacturing complexity increases due to extensive machining and forming requirements
Solution Approach 1:
The patent applies preliminary action by pre-treating the titanium material with hydrogen atmosphere and thermal cycles before final manufacturing. This preliminary microstructural refinement enables the material to achieve desired mechanical properties directly from near-net-shape components, eliminating the need for extensive subsequent machining and forming operations.
3Use of energy by moving object
If near-net-shape technologies like casting and additive manufacturing are used, then energy consumption is reduced, but microstructure quality deteriorates producing coarse or acicular structures
Solution Approach 1:
The patent applies parameter changes by subjecting near-net-shape titanium components to controlled thermal-hydrogen treatment. By adjusting temperature (above and below beta transus) and hydrogen atmosphere conditions, the microstructure is refined from coarse or acicular forms to fine-grained structures with improved mechanical properties, while maintaining the energy efficiency advantages of near-net-shape manufacturing.
4Adaptability or versatility
If laser AM is used to produce titanium components, then complex geometries are achieved, but mechanical properties become highly anisotropic with poor ductility
Solution Approach 1:
The patent applies parameter changes through hydrogen atmosphere treatment and thermal cycling (above and below beta transus temperature) to isotropize the microstructure of laser AM titanium components. This treatment refines the highly anisotropic acicular microstructure into a more uniform fine-grained structure, significantly improving ductility and mechanical properties while preserving the geometric complexity advantages of additive manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process produces titanium materials with ultrafine-grained, globularized, and bi-modal microstructures, enhancing mechanical properties such as ductility and fatigue strength without the energy costs of traditional methods.
Implementation Method 1
The titanium material can be heated under a hydrogen-containing atmosphere to a hydrogen charging temperature. The hydrogen charging temperature can be above a β transus temperature of the titanium material and below a melting temperature of the titanium material. The titanium material can be held at this temperature for a hydrogen charging time sufficient to convert the titanium material to a substantially homogeneous β phase titanium material.
Implementation Method 2
The titanium material can be cooled under the hydrogen-containing atmosphere to a phase transformation temperature. The phase transformation temperature can be below the β transus temperature and above about 400° C. The titanium material can be held at the phase transformation temperature for a phase transformation time to produce regions of the lower temperature α, α2, and in some cases δ phases.
Implementation Method 3
The method can include holding the titanium material under a substantially hydrogen-free atmosphere or vacuum at a dehydrogenation temperature to form a dehydrogenated titanium material. The dehydrogenation temperature can be below the β transus temperature of the hydrogen-free titanium material and above the decomposition temperature of the δ phase, about 200° C. for some alloys. This can remove at least a portion of hydrogen from the titanium material.
Data Source
AI summary
A method of modifying a microstructure of a titanium material can include providing a solid titanium material in an inert atmosphere, where the solid titanium material has an initial microstructure with an initial grain size and which is optionally anisotropic. The method can also include introducing hydrogen through a thermal process into the solid titanium material, resulting in a titanium alloy article having a refined microstructure that has a final grain size that is smaller than the initial grain size, or reduced anisotropy, or a combination thereof.