Titanium Alloy Composition for Thick-Section Turbine Strength
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Solution Overview
Problem
Current titanium alloys used in gas turbine engines, such as Ti-64, have limited thick section strength and high-cycle fatigue capability, especially at low A ratios, and are prone to deformation during foreign object damage (FOD), while alloys like Ti-17 and Ti-6246 offer better strength and temperature resistance but are more expensive and less manufacturable.
Innovation Solution
A new titanium alloy composition with 5-8 wt% aluminum, 2.5-5.5 wt% vanadium, 0.1-2 wt% iron or molybdenum, 0.01-0.2 wt% carbon, up to 0.3 wt% oxygen, and optional silicon or copper, designed to maintain the isotropic properties and low cost of Ti-64 while enhancing thick section strength and fatigue resistance, using a processing method that includes hot working and solution heat treatment to achieve a refined microstructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Ti-64 alloy is used for rotary components, then cost and manufacturability are improved, but thick section strength and high-cycle fatigue capability deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of Ti-64 by adding specific amounts of beta-stabilizing elements (Mo: 0.5-2.0 wt%, Fe: 0.1-1.0 wt%, Cu: 0.1-1.0 wt%, Si: 0.1-1.0 wt%) to change the material's microstructural properties and improve thick section strength while maintaining manufacturability
Solution Approach 2:
The invention creates a composite alloy system by combining Ti-64 base material with multiple beta-stabilizing elements that work synergistically to enhance strength properties in thick sections while preserving the base alloy's processing characteristics
2Strength
If Ti-17 or Ti-6246 alloy is used for rotary components, then thick section strength and temperature resistance are improved, but cost and manufacturability deteriorate
Solution Approach 1:
The patent applies local quality by adding beta-stabilizing elements specifically to enhance thick section properties where needed, while maintaining the overall Ti-64 alloy's favorable processing characteristics and isotropic properties that benefit manufacturing
Solution Approach 2:
The invention changes the alloy composition parameters by incorporating controlled amounts of Mo, Fe, Cu, and Si to achieve improved thick section strength comparable to Ti-17 and Ti-6246, while retaining the cost-effectiveness and manufacturability of Ti-64
3Ease of manufacture
If Ti-64 alloy is used for rotary components, then cost and isotropic properties are improved, but high-cycle fatigue capability at low A ratio deteriorates
Solution Approach 1:
The patent modifies composition parameters by adding beta-stabilizing elements (Mo, Fe, Cu, Si) that refine the microstructure and improve high-cycle fatigue capability at low A ratios, while maintaining the cost-effectiveness of Ti-64 through controlled addition levels
4Weight of moving object
If Ti-64 alloy is used for rotary components, then density and FOD tolerance are improved, but deformation during foreign object damage deteriorates
Solution Approach 1:
The invention changes material parameters by incorporating beta-stabilizing elements that enhance strength and reduce deformation during FOD events, while maintaining the low density characteristic of Ti-64 through controlled composition adjustments
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 new alloy achieves improved thick section strength, high-cycle fatigue capability, and reduced deformation during FOD, while maintaining the cost-effectiveness and manufacturability of Ti-64, with enhanced performance in temperature-resistant applications.
Implementation Method 1
hot working a titanium alloy ingot at a temperature that is above the beta transus temperature
Implementation Method 2
solution heat treating the forged component at a temperature that is below the beta transus and the silicide solvus temperature
Implementation Method 3
hot working the titanium alloy ingot at a temperature that is below both the beta transus temperature of the alloy and the silicide solvus temperature
Data Source
AI summary
A composition of matter is generally provided, in one embodiment, a titanium alloy comprising 5 wt % to 8 wt % aluminum; 2.5 wt % to 5.5 wt % vanadium; 0.1 wt % to 2 wt % of one or more elements selected from the group consisting of iron and molybdenum; 0.01 wt % to 0.2 wt % carbon; up to 0.3 wt % oxygen; silicon and copper; and titanium. A turbine component is also generally provided, in one embodiment, that comprises an article made from a titanium alloy. Additionally, methods are also generally provided for making an alloy component having a beta transus temperature and a titanium silicide solvus temperature.