Carbonitrided Metal Core for Hot Shaping Titanium Alloy Parts
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Solution Overview
Problem
The existing methods for manufacturing titanium-based alloy shields for turbine blade leading edges are costly and inefficient due to high tool wear, complex shapes, and difficulty in achieving thin thicknesses and small radii, with yttrium oxide coating being expensive and non-uniform, and carbonitriding processes being time-consuming.
Innovation Solution
A metal core made of a nickel or cobalt alloy with chromium, molybdenum, and titanium, coated with a steel layer enriched in metal carbonitride, allowing for hot shaping of titanium-based alloys into complex geometries without bonding or contamination, enabling reuse and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If forging from alloy bar with successive stages of bending, tamping and spinning is used to manufacture titanium alloy shields, then the shields can be manufactured with complex shapes, but the manufacturing cost increases due to significant wear of forging tools and a large number of manufacturing steps
Solution Approach 1:
The invention changes the manufacturing approach by using hot forming at elevated temperatures (typically 900-1100°C) instead of cold forging. This parameter change allows the titanium alloy to become more formable, enabling complex shield geometries to be achieved in fewer steps with reduced tool wear, as the material is more ductile at high temperature
Solution Approach 2:
The invention introduces a diffusion barrier coating (such as yttrium oxide, aluminum oxide, or nickel-based coatings) as an intermediary layer between the titanium alloy shield and the forging tools. This coating prevents direct contact and chemical reaction between the titanium and tooling, significantly reducing tool wear and allowing for more manufacturing cycles
2Ease of manufacture
If hot forming around a core with yttrium oxide coating is used to manufacture titanium alloy shields, then the manufacturing process can be simplified, but the coating degrades quickly and cannot be reused
Solution Approach 1:
The invention uses composite coating structures such as nickel-aluminum alloys or multi-layer coatings combining different materials (e.g., yttrium oxide on nickel base). These composite coatings provide both the diffusion barrier function and enhanced mechanical durability, allowing the core to be reused multiple times while maintaining protection against titanium diffusion and oxidation
Solution Approach 2:
The invention optimizes the coating parameters including thickness (typically 10-50 micrometers), composition ratios, and application methods to achieve a balance between diffusion barrier effectiveness and mechanical durability. The coating is designed to withstand repeated thermal cycling and mechanical stresses during hot forming operations
3Reliability
If carbonitriding treatment is applied to nickel- or cobalt-based alloy core to form diffusion barrier, then the barrier between metal alloy core and titanium-based alloy part is formed, but the treatment takes more than 100 hours
Solution Approach 1:
The invention changes the surface chemistry parameters of the nickel or cobalt-based core by controlling the carbon and nitrogen content, ratios, and distribution during carbonitriding. By optimizing these parameters, a effective diffusion barrier is formed that prevents titanium contamination while significantly reducing the treatment time from over 100 hours to a more practical duration
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 method allows for the efficient hot shaping of titanium-based alloys into complex geometries with high fatigue resistance, reducing manufacturing costs and extending the life of the metal core through regeneration, while preventing contamination and bonding issues.
Implementation Method 1
a steel coating having an outer surface intended to come into contact with the metal part, the steel coating having a layer of material enriched in metal carbonitride
Implementation Method 2
the layer of material enriched in metal carbonitride... forms a diffusion barrier between the metal alloy of the core and the titanium-based alloy of the metal part to be shaped
Implementation Method 3
hot conformation makes it possible, by hot plastic deformation of the metal part, to manufacture a part of complex three-dimensional geometry
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5E
AI summary
The invention relates to a metal core (20) for high-temperature shaping of a metal part made of titanium-based alloy. The metal core (20) has a layer of material enriched in metal carbonitride on an outer surface (23) intended to come into contact with the metal part. The metal core (20) comprises an alloy based on nickel or cobalt. The metal core (20) comprises a steel coating (20B) having an outer surface (23) which is intended to come into contact with the metal part, the steel coating (20B) having a layer of material enriched in metal carbonitride (24). The invention also relates to processes for manufacturing and regenerating the metal core (20) and to a process for the high-temperature shaping of a metal part using the metal core (20).