Beta Titanium Alloy Composition for Stable BCC Processing

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Solution Overview

Problem

Conventional titanium alloys face challenges in achieving a single phase body-centered cubic (bcc) solid solution structure below the solidus temperature, which limits their production processes and properties such as strength and ductility, especially at elevated temperatures.

Innovation Solution

A titanium alloy composition with a range of 2.0 - 6.0 wt.% Al, 4.0 - 12.0 wt.% V, and 1.0 - 5.0 wt.% Fe, along with optional incidental elements, is developed to achieve a bcc solid solution structure, allowing for conventional ingot processing, powder metallurgy, and additive manufacturing, while controlling cooling rates to form a crack-free ingot with precipitate phases for enhanced properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional titanium alloy compositions are used, then the alloy can be processed using standard methods, but the alloy cannot achieve a single phase bcc solid solution structure below the solidus temperature

Engineering Contradiction:
Improvesingle phase bcc solid solution structureVSAvoidprocessing capability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the compositional parameters of alloying elements (Al: 2.0-6.0 wt.%, V: 4.0-12.0 wt.%, Fe: 1.0-5.0 wt.%) to transform the phase structure from conventional alpha or alpha-beta mixtures to a single phase bcc solid solution structure below the solidus temperature, while maintaining processability through conventional methods

Inventive Principle:
Principle #35Parameter changes

2Strength

If the alloy composition is optimized for bcc structure, then mechanical properties and thermal stability improve, but the freezing range narrows causing restricted hot cracking and microsegregation

Engineering Contradiction:
Improvetensile yield strengthVSAvoidmicrosegregation control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent utilizes phase transitions by designing the alloy composition to achieve a narrow freezing range that promotes restricted hot cracking during solidification, while the bcc phase structure provides the desired mechanical properties and thermal stability, balancing manufacturing precision with performance

Inventive Principle:
Principle #36Phase transitions

3Strength

If aluminum content is increased to enhance strength, then tensile yield strength improves, but the beta transus temperature increases reducing thermal stability

Engineering Contradiction:
Improvetensile yield strengthVSAvoidbeta transus temperature
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent applies parameter changes by optimizing the aluminum content within a specific range (2.0-6.0 wt.%) and balancing it with vanadium (4.0-12.0 wt.%) and iron (1.0-5.0 wt.%) to achieve the desired strength while controlling the beta transus temperature to maintain thermal stability for high-temperature applications

Inventive Principle:
Principle #35Parameter changes

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 exhibits improved mechanical properties, including higher tensile yield strength and elongation, and thermal stability, making it suitable for various applications like aerospace and automotive components with reduced microsegregation and hot cracking.

Implementation Method 1

a narrow equilibrium freezing range (e.g., for restricting microsegregation during solidification)

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

Some small fraction of alpha phase (hcp) may be present through a solid-state transformation at a low temperature in the alloy

Methodology Applied
Scientific EffectSolid-state transformation: Phase Change

Data Source

PatentEP3449025B1Bcc materials of titanium, aluminum, vanadium, and iron, and products made therefrom
Publication Date: 2023.08.23 HOWMET AEROSPACE INC

AI summary

New beta-style (bcc) titanium alloys are disclosed. The new alloys generally include 2.0 - 6.0 wt. % Al, 4.0 - 12.0 wt. % V, and 1.0 - 5.0 wt. % Fe, the balance being titanium, any optional incidental elements, and unavoidable impurities. The new alloys may realize an improved combination of properties as compared to conventional titanium alloys.