Beta-Style Titanium Alloy Composition for Additive Manufacturing

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Solution Overview

Problem

Existing titanium alloys face challenges in achieving a single phase field of a body-centered cubic (bcc) solid solution structure below their solidus temperature, which limits their manufacturing processes and properties such as ductility and strength.

Innovation Solution

Development of new titanium alloys with specific compositions of titanium, aluminum, niobium, vanadium, and molybdenum, optionally with chromium, that exhibit a bcc crystalline structure and a low beta transus temperature, allowing for a stable solid solution strengthened matrix and controlled cooling processes to produce crack-free ingots and products with enhanced properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional titanium alloys are used, then manufacturing processes are limited, but achieving a single phase field of bcc solid solution structure below solidus temperature is difficult

Engineering Contradiction:
Improvesingle phase field of bcc solid solution structureVSAvoidmanufacturing processes
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of titanium alloys, specifically adding beta-stabilizing elements (Nb, V, Mo, Al) in controlled amounts to shift the phase stability parameters. This enables the formation of a single bcc solid solution phase field that extends to lower temperatures below the solidus, which is the key parameter change needed to resolve the contradiction between phase stability and manufacturability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite material systems by combining titanium with multiple alloying elements (Nb, V, Mo, Al, Cr) to form a new alloy composition system. This composite approach allows the material to achieve a stable single-phase bcc structure that conventional pure titanium or simple titanium alloys cannot attain, thereby enabling both the desired phase stability and expanded manufacturing options.

Inventive Principle:
Principle #40Composite materials

2Temperature

If beta transus temperature is reduced, then stable solid solution strengthened matrix is achieved, but alloy composition control becomes more critical

Engineering Contradiction:
Improvebeta transus temperatureVSAvoidalloy composition control
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent systematically adjusts multiple compositional parameters simultaneously (adding 4-8 wt% Nb, 4-8 wt% V, 1.5-4.5 wt% Mo, and 4.5-7.5 wt% Al) to achieve the target beta transus temperature reduction to below 850°C. This multi-parameter adjustment approach allows precise control over the phase transformation temperature while maintaining a stable solid solution matrix.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses beta-stabilizing alloying elements as intermediary substances that mediate between the titanium matrix and the desired low beta transus temperature. These intermediary elements (particularly Nb, V, and Mo) act as compositional buffers that enable fine-tuning of the phase transformation temperature while maintaining overall alloy stability and solid solution strengthening.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If alloy composition is optimized for bcc structure, then mechanical properties improve, but material cost increases

Engineering Contradiction:
Improvemechanical propertiesVSAvoidalloy composition
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent optimizes the concentration parameters of alloying elements to achieve the minimum necessary amounts for forming a stable single-phase bcc structure. By carefully controlling the composition parameters (e.g., 4.5-7.5 wt% Al, 1.5-4.5 wt% Mo, 4-8 wt% Nb and V), the patent achieves improved mechanical properties while minimizing the quantity of expensive alloying elements required, thus balancing performance with material cost.

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 alloys achieve a stable bcc solid solution structure with improved mechanical properties, including strength and ductility, making them suitable for various applications like aerospace and automotive components, and enabling production through conventional ingot processing, powder metallurgy, and additive manufacturing.

Implementation Method 1

the new materials may realize a single phase field of a bcc solid solution structure immediately below the solidus temperature of the material

Methodology Applied
Scientific EffectSolid solution strengthening: Solid Solution Strengthening

Implementation Method 2

cooling the mixture from above the liquidus temperature to below the solidus temperature, wherein, due to the cooling, the mixture forms a solid product having a bcc (body-centered cubic) solid solution structure

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Implementation Method 3

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

PatentEP3449024B1Bcc materials of titanium, aluminum, niobium, vanadium, and molybdenum, and additive manufacturing method using said materials
Publication Date: 2020.12.30 HOWMET AEROSPACE INC
  • EP3449024B1 patent drawingFigure 1
  • EP3449024B1 patent drawingFigure 2a
  • EP3449024B1 patent drawingFigure 2b

AI summary

New beta-style (bcc) titanium alloys are disclosed. The new alloys generally include 4 - 8 wt. % Al, 4-8 wt. % Nb, 4-8 wt. % V, 1-5 wt. % Mo, optionally 2-6 wt. % Cr, the balance being titanium, optional incidental elements, and unavoidable impurities. The new alloys may realize an improved combination of properties as compared to conventional titanium alloys.