Layered Titanium Composite for Low-Cost Corrosion-Resistant Hot Working
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Solution Overview
Problem
The high production cost of titanium alloys due to the use of scarce and expensive platinum group elements, combined with issues related to formability, oxidation resistance, and hydrogen embrittlement, limits the cost-effective production of titanium materials with desired characteristics such as corrosion resistance, fatigue resistance, and neutron blocking properties.
Innovation Solution
A titanium material for hot working is developed, comprising a package with a titanium alloy outer layer and a commercially pure titanium inner layer, where the titanium alloy is composed of specific elements like platinum group elements, rare earth elements, and boron, and the material is processed under a reduced pressure vacuum to reduce the content of expensive alloying elements and enhance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum group elements are added to titanium to improve corrosion resistance, then corrosion resistance is improved, but production cost increases significantly
Solution Approach 1:
The patent applies local quality by creating a composite structure where only the outer surface layer contains platinum group elements (0.01-0.25%) while the inner core uses inexpensive commercially pure titanium. This localized alloying provides corrosion resistance only where it is needed (at the surface exposed to corrosive environments) while minimizing the use of expensive alloying elements, thereby resolving the contradiction between corrosion resistance and production cost.
Solution Approach 2:
The patent uses composite materials by combining commercially pure titanium with a titanium alloy containing platinum group elements in a layered structure. The commercially pure titanium provides structural integrity and low cost, while the titanium alloy layer provides enhanced corrosion resistance. This composite approach allows achieving high corrosion resistance without the prohibitive cost of using platinum group elements throughout the entire material.
2Strength
If heat-resistant alloying elements are added to improve high temperature strength, then high temperature strength is improved, but cost increases compared to commercially pure titanium
Solution Approach 1:
The patent applies local quality by concentrating heat-resistant alloying elements (Al: 0.3-1.5%, Si: 0.1-0.6%, Nb: 0.1-2.0%) in the outer titanium alloy layer rather than distributing them throughout the entire material. This localized approach provides high temperature strength and oxidation resistance at the surface where these properties are most needed, while the inner core remains as cost-effective commercially pure titanium.
Solution Approach 2:
The patent uses composite materials by creating a layered structure combining commercially pure titanium with a heat-resistant titanium alloy. The alloy layer containing Al, Si, and Nb provides enhanced high temperature strength and oxidation resistance, while the commercially pure titanium core provides structural support at lower cost, resolving the contradiction between high temperature strength and cost.
3Reliability
If alloying elements are added to improve oxidation resistance, then oxidation resistance is improved, but formability deteriorates
Solution Approach 1:
The patent applies local quality by providing oxidation resistance only in the outer titanium alloy layer that is exposed to oxidizing environments, while the inner commercially pure titanium layer maintains excellent formability. The alloying elements (Al: 0.3-1.5%, Si: 0.1-0.6%) are concentrated at the surface where oxidation protection is needed, without compromising the formability of the bulk material.
Solution Approach 2:
The patent uses composite materials by combining a titanium alloy layer with enhanced oxidation resistance with a commercially pure titanium layer that provides good formability. The layered composite structure allows the material to exhibit both oxidation resistance (from the alloy layer) and good formability (from the pure titanium core), resolving the contradiction between these two properties.
4Reliability
If expensive alloying elements are used to achieve desired material characteristics, then material performance is improved, but production cost increases
Solution Approach 1:
The patent applies local quality by concentrating expensive alloying elements (platinum group elements, rare earth elements, Al, Si, Nb) only in the outer titanium alloy layer where they are needed to provide enhanced performance characteristics. The inner core uses inexpensive commercially pure titanium, significantly reducing the overall amount of expensive materials required while maintaining desired performance properties.
Solution Approach 2:
The patent uses composite materials by creating a layered structure that combines expensive titanium alloy with inexpensive commercially pure titanium. This composite approach allows achieving high material performance (corrosion resistance, oxidation resistance, strength) through the alloy layer while minimizing production cost by using the cheaper commercially pure titanium for the bulk of the material.
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
This approach allows for the cost-effective production of titanium materials with enhanced corrosion resistance, oxidation resistance, fatigue resistance, and neutron blocking properties, while maintaining equivalent performance to materials made entirely of titanium alloy.
Implementation Method 1
the material is processed under a reduced pressure vacuum to reduce the content of expensive alloying elements and enhance properties
Data Source
Figure 1~2
Figure 3~4(d)
Figure 5
AI summary
Provided is a titanium composite material 1 including: a first surface layer portion 2; an inner layer portion 4; and a second surface layer portion 3; wherein: the first surface layer portion 2 and the second surface layer portion 3 are composed of a titanium alloy; the inner layer portion 4 is composed of a commercially pure titanium including pores; a thickness of at least one of the first surface layer portion 2 and the second surface layer portion 3 is 2 µm or more, and a proportion of the thickness with respect to an overall thickness of the titanium composite material 1 is 40% or less; and a porosity in a cross section perpendicular to a sheet thickness direction is more than 0% and 30% or less.