Alpha-Beta Titanium Alloy Thermomechanical Processing
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Solution Overview
Problem
Current methods for processing alpha-beta titanium alloys to achieve fine, superfine, or ultrafine grain microstructures are limited by slow strain rates, high processing times, and the need for custom equipment, making them economically unfeasible for industrial-scale production.
Innovation Solution
A method involving multiple temperature ranges and forging processes, including upset and draw forging, radial forging, and slow cooling, to refine alpha-phase grain size in alpha-beta titanium alloys, allowing for higher strain rates and reducing processing time without requiring custom equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultra-slow strain rate multi-axis forging or ECAP process is used to achieve ultrafine grain microstructure, then grain refinement is improved, but processing time increases excessively and equipment complexity increases
Solution Approach 1:
The patent changes the strain rate parameter from ultra-slow (0.001 s−1 or slower) to a more practical range, and modifies the temperature parameter by introducing a two-stage heating process. This allows achieving ultrafine grain microstructure without the excessively long processing times required by conventional ultra-slow strain rate methods
Solution Approach 2:
The patent applies a preliminary heating stage to austenite before the main forging operation. This preliminary thermal preparation enables the subsequent forging to achieve grain refinement more efficiently, reducing the total processing time compared to direct ultra-slow strain rate forging
2Manufacturing precision
If ultra-slow strain rate multi-axis forging or ECAP process is used to achieve ultrafine grain microstructure, then grain refinement is improved, but device complexity increases due to custom equipment requirements
Solution Approach 1:
The patent adapts conventional forging equipment to perform the two-stage heating and forging process, making the ultrafine grain production method compatible with existing industrial equipment rather than requiring custom-built ultra-slow strain rate facilities. This universality reduces equipment complexity and investment costs
3Loss of time
If conventional forging methods are used to produce coarse or fine grain microstructure, then processing time is reduced, but grain refinement is insufficient
Solution Approach 1:
The patent segments the heating process into two distinct stages: preliminary heating to austenite temperature, followed by controlled cooling and forging. This segmentation allows each stage to be optimized independently, achieving both time efficiency and superior grain refinement that conventional single-stage methods cannot achieve
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 method effectively refines alpha-phase grain size, improving ductility and enabling the production of titanium alloys with fine to ultrafine grain microstructures at a lower cost and with increased efficiency, suitable for industrial-scale production.
Implementation Method 1
The key to grain refinement in the ultra-slow strain rate MAF and the ECAP processes is the ability to continually operate in a regime of dynamic recrystallization that is a result of the ultra-slow strain rates used
Implementation Method 2
The alloy is slow cooled from the first working temperature. On completion of working at and slow cooling from the first working temperature, the alloy comprises a primary globularized alpha-phase particle microstructure
Data Source
AI summary
One embodiment of a method of refining alpha-phase grain size in an alpha-beta titanium alloy comprises working an alpha-beta titanium alloy at a first working temperature within a first temperature range in the alpha-beta phase field of the alpha-beta titanium alloy. The alloy is slow cooled from the first working temperature. On completion of working at and slow cooling from the first working temperature, the alloy comprises a primary globularized alpha-phase particle microstructure. The alloy is worked at a second working temperature within a second temperature range in the alpha-beta phase field. The second working temperature is lower than the first working temperature. The is worked at a third working temperature in a third temperature range in the alpha-beta phase field. The third working temperature is lower than the second working temperature. After working at the third working temperature, the titanium alloy comprises a desired refined alpha-phase grain size.