Titanium Alloy Composition for Strength and Ductility Balance
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Solution Overview
Problem
Current titanium alloys face challenges in achieving a balanced combination of strength, ductility, creep resistance, dwell fatigue life, and low cycle fatigue life, which limits their application in aerospace and automotive industries.
Innovation Solution
A new titanium alloy composition is developed, ranging from 4.75 to 6.75 wt.% Al, 6.75 to 8.5 wt.% (Nb + Ta), with 1.5 to 3.5 wt.% Sn, up to 5.0 wt.% Zr, and up to 2.5 wt.% Mo, along with incidental elements and impurities, to optimize these properties through controlled cooling and precipitation hardening processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum content is increased to improve strength and creep resistance, then strength and creep resistance are improved, but excessive aluminum forms α2-Ti3Al phase that reduces ductility
Solution Approach 1:
The patent optimizes the aluminum content parameter within a specific range (4.5-7.5 wt.%) to achieve the desired balance between strength and ductility. By controlling the aluminum concentration parameter, the alloy gains sufficient strength and creep resistance while avoiding excessive formation of the brittle α2-Ti3Al phase that would harm ductility.
Solution Approach 2:
The patent creates a composite microstructure consisting of multiple phases (α phase, β phase, and controlled α2 precipitates) through specific alloying composition. This composite phase structure allows the material to simultaneously achieve high strength from the precipitates and good ductility from the matrix phases, resolving the contradiction between strength and ductility.
2Strength
If niobium and tantalum content is increased to improve creep resistance and strength, then creep resistance and strength are improved, but excessive niobium and tantalum reduce creep resistance
Solution Approach 1:
The patent optimizes the combined content of niobium and tantalum within a specific range (6.75-8.5 wt.%) to achieve the desired balance between strength and creep resistance. By controlling this parameter, the alloy gains sufficient creep resistance and strength while avoiding excessive beta phase formation that would harm long-term creep performance.
Solution Approach 2:
The patent creates local phase distribution with controlled beta phase regions dispersed in the matrix. The niobium and tantalum elements locally stabilize beta phase in specific regions, providing strength through precipitation hardening while maintaining overall creep resistance through controlled phase distribution, rather than uniform beta phase formation.
3Strength
If tin content is increased to improve strength, then strength is improved, but excessive tin forms α2-Ti3Al phase that reduces ductility
Solution Approach 1:
The patent optimizes the tin content parameter within a specific range (1.5-3.5 wt.%) to achieve the desired balance between strength and ductility. By controlling the tin concentration parameter, the alloy gains sufficient strength through solid solution strengthening and precipitation hardening while avoiding excessive formation of the brittle α2-Ti3Al phase that would harm ductility.
4Strength
If molybdenum content is increased to improve strength, then strength is improved, but excessive molybdenum impacts creep resistance
Solution Approach 1:
The patent optimizes the molybdenum content parameter within a specific range (up to 2.5 wt.%) to achieve the desired balance between strength and creep resistance. By controlling the molybdenum concentration parameter, the alloy gains sufficient strength through solid solution strengthening and beta phase stabilization while avoiding excessive molybdenum that would form harmful intermetallic phases and harm creep resistance.
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 strength, ductility, creep resistance, and fatigue life, making it suitable for various applications, including aerospace and automotive components, with enhanced mechanical properties at elevated temperatures.
Implementation Method 1
the new titanium alloys may realize an improved combination of properties, such as, an improved combination of at least two of strength, ductility, creep resistance, dwell fatigue life, low cycle fatigue life, and dwell fatigue life debit due to their composition and methods of production
Implementation Method 2
to optimize these properties through controlled cooling and precipitation hardening processes
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
The present disclosure relates to new titanium alloys and methods for making the same. The new titanium alloys generally include 4.75 - 6.75 wt. % Al, 6.5 - 8.5 wt. % (Nb + Ta), 1.5 - 3.5 wt. % Sn, up to 5.0 wt. % Zr, and up to 2.5 wt. % Mo, the balance being titanium, optional incidental elements, and impurities. Due to their composition and methods of manufacture, the new titanium alloys may find use in several applications, such as aerospace and/or automotive applications.