Titanium Alloy Composition for Fine β-Grains in Additive Manufacturing
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Solution Overview
Problem
Conventional methods for manufacturing titanium components, such as casting and forging, face challenges like high material waste, long lead times, and inability to produce complex shapes with refined grain structures, which affect the mechanical properties of the components.
Innovation Solution
The development of titanium alloys with specific compositions, including aluminum, molybdenum, and bismuth, that promote grain refinement and isotropic high-strength mechanical properties, particularly suited for direct energy deposition additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additive manufacturing is used to manufacture titanium components, then productivity is improved and material waste is reduced, but the grain structure becomes coarse and mechanical properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the titanium alloy by adding specific elements (Nb: 1-5 wt%, Mo: 1-4 wt%, W: 1-4 wt%, Ta: 1-3 wt%) to modify the solidification behavior and achieve fine grain structure through compositional control rather than mechanical processing
Solution Approach 2:
The patent creates a multi-element composite titanium alloy system combining α-stabilizers (Al, Sn, Zr), β-stabilizers (Nb, Mo, W, Ta, V), and other elements to achieve synergistic effects that refine grain structure while maintaining the benefits of additive manufacturing
2Strength
If conventional thermo-mechanical processing is used to refine grain structure, then mechanical properties are improved, but the manufacturing complexity and lead time increase
Solution Approach 1:
The patent replaces mechanical grain refinement methods (forging, rolling, extrusion) with chemical composition control that enables spontaneous fine grain formation during additive manufacturing solidification, eliminating the need for complex thermo-mechanical processing equipment and steps
3Manufacturing precision
If mechanical deformation is applied to recrystallize grains in additive manufactured components, then grain structure is refined, but the effective deposition rate decreases
Solution Approach 1:
The patent performs preliminary grain refinement through chemical composition design before the additive manufacturing process begins, so that fine grains form automatically during solidification without requiring subsequent mechanical deformation steps that would reduce deposition rate
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
The use of these titanium alloys results in components with significantly refined prior β-grain sizes, improved strength, fatigue resistance, and isotropic properties, overcoming the limitations of traditional manufacturing methods.
Implementation Method 1
the low surface tension element Bi
Implementation Method 2
promote grain refinement
Implementation Method 3
solidifies and cools down
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
The present invention relates to titanium alloy compositions suited for manufacturing components by additive manufacturing, resulting in components that exhibit relatively small prior β-grain sizes. The titanium alloy compositions comprises: from 2 to 7 wt% Al, from 1.5 to 6 wt% Mo, from 0.25 to 1.5 wt% Bi, unavoidable impurities, and a remaining wt% Ti which makes the total content of constituents in the titanium alloy composition sum up to 100 wt%, wherein the weight percentages are based on the total mass of the titanium alloy composition.